Propeller-controlled active tuned-liquid-column damper

Propeller-controlled active tuned-liquid-column damper 
https://www.google.com/patents/US6857231
objective of this lit : semi active tlcd with propellor to control the flow of water.

The TMD has the optimal performance in vibrational control, if the natural period and damping ratio of this TMD are equal to the corresponding tuned period and the optimal damping ratio, respectively. Usually the tuned period is very close to the fundamental period of the structure whose vibration is required to be controlled.

The practical application of TMD is somewhat restricted and limited, this is due to the fact that the mass of TMD is heavy, the mechanism of the spring (4) and dashpot (5) system is complicated and not easy to maintain, it needs large space for TMD and its motion, it needs large power to control the motion of the mass block (3) if an active-control technique is applied, and the structure of the active control system of TMD is also complicated and not easy to maintain. Therefore TMD is not quite popular in practice, particularly for the large structures like a high-rise building.

2. Tuned Liquid Damper (or TLD)
A plane frame with a TLD is shown in FIG. 2. The structure of a TLD is quite simple, it is a liquid tank (7) partially filled with liquid (or water) (8). An appropriately designed water-storing tank on the roof of a high-rise building can serve as a TLD. The liquid weight of TLD is about 0.5˜2.0% of the total weight of a structure which is under vibrational control. The fluid sloshing and oscillation inside the fluid tank (7) due to resonance can provide the force opposite to the direction of the vibration of the structure and can reduce the vibration efficiently.

The fundamental period of TLD can be adjusted by changing the shape and the dimensions (including the water depth) of the fluid tank (7). The TLD has the optimal performance in vibrational control, if the fundamental period and the damping ratio of this TLD are equal to the corresponding tuned period and the optimal damping ratio, respectively. Usually the tuned period is very close to the fundamental period of the structure under vibrational control.

Although the structure of TLD is simple i.e. a fluid tank (7) and its inside fluid (8), the practical application of TLD is still very limited, particularly for the high-rise building. This is due to the fact that the tuned period of TMD is not easy to be achieved, the mechanism to achieve the optimal damping ratio of a TLD is complicated and not easy to be designed. Furthermore the active-control technique is not easy to be applied to TLD so far, all the practical applications of TLD is only limited to the passive TLD, the active TLD is still not practical and it needs more efforts of future research

3. Tuned Liquid-Column Damper (or TLCD)
A plane frame with a TLCD is shown in FIG. 3. The structure of a TLCD is also quite simple, it is a long U-shape vessel (9) partially filled with fluid (or water) (8). The U-shape vessel (9) is a long circular or rectangular tube as shown in FIGS. 4 and 5. The length of the tube should be at least ten times greater than the diameter or the in-plane dimension of the cross section. The cross section of a TLCD can either uniform or non-uniform, but it is usually symmetrical about the vertical center line of a TLCD. The ends of the vertical columns of a TLCD are usually open. The fluid weight of a TLCD is also about 0.5˜2.0% of the total weight of a structure under vibrational control.

The fluid flow and oscillation inside the U-shape vessel (9) due to resonance can provide a force opposite to the direction of the vibration and can reduce the vibration of the structure effectively. The natural period of a TLCD can be adjusted by changing the wetted length of the U-shape vessel (i.e. the sum of the length of the horizontal section and the water heads of the vertical columns). The TLCD has the optimal performance in vibrational control, if the natural period and the damping ratio of this TLCD are equal to the corresponding tuned period and the optimal damping ratio, respectively. Usually the tuned period is very close to the fundamental period of the structure under vibration control. In general the damping ratio of a TLCD is small than the optimal damping ratio in practice; therefore the properly-designed artificial orifices, which are made of the buffers (10), installed inside the horizontal section of a TLCD are necessary to achieve the optimal damping ratio. The damping ratio of a TLCD with orifices is strongly dependent of the shape, size, and number of the orifices, and it can be predicted by the test and engineering experience or judgment.

The natural period of an open TLCD can be adjusted by only changing the wetted length; therefore the tuned period for a TLCD is not easy to be achieved and usually we need a great number of TLCD’s in practice. This is why the practical application of TLCD is still quite limited, particularly for the high-rise buildings. The air-compressor control system can accelerate the fluid flow to increase the vibrational-control ability of a TLCD, but the structure of the air-compressor control system including the air valves is complicated and not easy to maintain.
Technique
They used propeller in the path of liquid flow to control the motion.

Performance enhancement of wind turbine systems with vibration control tuned column damper

Performance enhancement of wind turbine systems with vibration control: A review
Content : 
Damping by different method

Passive control 
A conventional vibration control technique, consisting of springs and dampers only, is referred as passive control device. (PED – passive energy decapitation)

Active control
The active control system provides enhanced structural behavior of a system and it consists of force delivery devices, real-time data processors and sensors. Sensors sense the vibration and control actuators apply necessary torque (force) to control the vibration of the structure

Semi Active Control 
Compared to the passive control method where the Control forces are developed from the motion of the structure itself, appropriate adjustable mechanical devices are used to Provide control forces for semi-active method. Semi-active Approach has become attractive for structural vibration control applications due to controllable damping and low power requirement for operating damping devices.

Tuned Mass Dampers
TMD consists of a secondary mass placed top of the primary structure with spring and damping elements. It provides a frequency-dependent hysteresis characteristic that increases damping in the main structure.

Tuned Liquid Damper
Among different types of TLD,Tuned Liquid Column Damper(TLCD) is the most feasible and efficient damper to solve vibration problem due to high excitation force. A TLCD is generally modelled as U-shaped tube which is partially filled with a volume of liquid and attached to the top of the structure it acts as a mass of the damper. Other than u shape rectangular shape cross tube like containers are also proposed. Different types of tlds and their applications in structural vibrations are studied. TLCD can control 55% of vibration in wind turbine.

Controllable fluid dampers
Controllable fluid damper is a class of semi-active devices which uses controllable fluids inside the damper. Electrorheological (ER)and Magnetorheological(MR) fluid dampers are the two most commonly implemented controllable semi-active devices for structural vibration control. These types of dampers are very reliable because they contain no moving parts except piston. Controllable fluids of ER/Mr damper have the ability to change from free-flowing state to semisolid state when it comes to an electric (ER)or magnetic(MR) field. MR fluid was also implemented to design semi-active TLCD in [99] to overcome the shortcoming of passive system and to enhance their liability of the system. MR fluid was used in this study to design controllable valve for semi-active TLCD

Ball vibration absorber (BVA)
The BVA consists of a steel ball, an arc path and two steel plates which prevent the ball slides aside. When the base structure is excited, the ball rolls along the arc path and thus counters the excitation force by absorbing energy. Experimental result found that vibration response has been reduced to 39%of the displacement with the use of BVA

Spirical TLD
The spherical TLD consists of two layers of hemispherical shape containers which are partially filled with water. The radius of spherical containers is determined by itsFrequency and the mass of the sloshing water. The dynamic responses were reduced significantly using shake table test for different excitation loads

System controllers
System controllers are designed to improve the response of the system based on desired output.

Overview of tuned liquid dampers and possible ways of oscillation damping properties improvement

Nowadays tuned dampers are the essential part of
high-rise buildings and many others “dynamically
sensitive” engineering structures. They are widely
used in the world’s highest buildings for the damping
of wind and seismic induced mechanical vibrations
and improvement of building dynamic behavior. As a
result, higher and more flexible engineering structures
can be built.
Main idea of vibration damper is that damper mass
oscillates in counter phase to main structure. As a
result amplitudes of main structure oscillations are
reduced due to summation with damper oscillations.
So called tuned mass dampers – dampers where
main mass is solid body elastically or viscoelastically
connected with the main structure – are more widely
distributed in engineering structures [31]. Connection
stiffness is specially adjusted (tuned) to the particular
structure vibration frequency to obtain the damping
effect. The most straightforward type of tuned mass
damper – a heavy sphere suspended on a cable at the
top of the tower. This type of damper is widely used in
high-rise building.
In the last decades, the idea of tuned liquid dampers
(TLD) got an extension and development. Liquid –
mainly water – is used as damping mass in this type of
dampers. TLD is a cheap, simple in construction and
environmental friendly damper type. Such dampers
also can be used as an additional water reserve for the
building water supply and the fire-fighting systems.

The use of TLD in high-rise building started to
increase in the last decade. Main types and ways of
improvement of TLD are observed in consequent
sections.

Interior Design

Introduction

Interior design concerns itself with more than just the visual or ambient enhancement of an interior space; it seeks to optimize and harmonize the uses to which the built environment will be put. Thus, in the words of the U.S. Bureau of Labor Statistics, it is "practical, aesthetic, and conducive to intended purposes, such as raising productivity, selling merchandise, or improving life style." Interior design is a practice that responds to changes in the economy, organization, technology, demographics, and business goals of an organization.
As a human activity, interior design is centuries old. As a coherent profession identified by the label "interior designer," it is relatively recent. Many experts trace its beginnings to the early 20th century and the rise of interior decoration as a career separate from architecture. In the early decades, this practice focused largely on the residential arena. By the 1940s, the terms "interior design" and "interior designer" were used primarily by those individuals providing services to a small but growing number of business clients. After World War II, nonresidential design—offices, hotels, retail establishments, and schools—grew in importance as the country rebounded economically. Interior design is generally divided into two categories, residential and contract or commercial. Today, interior design is becoming increasingly specialized as buildings and materials get more complex technologically and regulations and standards more demanding.
The first national professional organization for interior designers, The American Institute of Interior Decorators (later, the American Institute of Interior Designers), was founded in 1931, and a second, the National Society of Interior Designers, in 1957. But it was not until the 1960s and 70s that independent organizations were established to assess qualifications for designers and design programs, thereby putting in place the cornerstones of the profession; standards for education, experience, and examination. These are the Interior Design Educators Council, the Foundation for Interior Design Education Research, and the National Council for Interior Design Qualification. In 1975, AID and NSID merged to form the American Society of Interior Designers. The International Interior Design Association was founded in 1994.

Efforts to bring about statutory licensing of interior designers, variously through title or practice acts, also began in the 1960s. In 1982, Alabama became the first state to enact legislation for the regulation of interior design. Today, 25 states and jurisdictions have adopted some form of regulation for interior design. A current list of interior design laws by state can be found on the ASID website.

Description

A. Professional Definition

Interior design is a multi-faceted profession in which creative and technical solutions are applied within a structure to achieve a built interior environment that solves the customer's problems and links space to business strategies and goals. These solutions are functional, enhance the quality of life and culture of the occupants, and are aesthetically attractive. Designs are created in response to and coordinated with the building shell, and acknowledge the physical location and social context of the project. Designs must adhere to code and regulatory requirements, and encourage the principles of environmental sustainability. Interior design can also influence the choice of real estate that will address the organization's needs through the architecture and design elements. The interior design process follows a systematic and coordinated methodology, including research, analysis, and integration of knowledge into the creative process, whereby the needs and resources of the client are satisfied to produce an interior space that fulfills the project goals.
Interior design includes a scope of services performed by a professional design practitioner, qualified by means of education, experience and examination, to protect and enhance the life, health, safety, and welfare of the public. For the full definition, consult the National Council for Interior Design Qualification.

B. Professional Role in the "Whole Building" Design Process

The interior design professional is extremely important in the "whole building" design process and should be contracted at the onset of the project, referred to as the pre-design phase or programming phase, with the other major disciplines, key stakeholders, client, and end-user contacts. The interior designer needs to work closely with the client to understand their business and space needs. This can be thought of as strategic programming. It should occur at the same time as the building program is conducted. By assisting the organization in understanding its needs, as well as analyzing and recommending ways to link the organization's mission, business, and work processes to an intelligent workplace and space strategy, the interior designer adds value to the client's organization and real estate. Excellent communication with the key members of the team helps define the challenges and each team member's expectations to ensure a successful project. The interior designer must communicate the intent or project plan and what "whole building" systems and architecture can be explored to meet client expectations. Thus, an integrated team approach is important, and the coordination and collaboration of all disciplines is essential to a successful solution.

C. Professional Strategies for Achieving Relevant Design Objectives

It really takes a team to get smarter solutions. Organize the team at the onset of the project. Include the building manager and most importantly a qualified design team with key disciplines and construction manager at the onset. The interior designer should no longer receive a plan from the architect to perform space planning, materials, and furniture selection. The basic principles of a workplace can address and include the following criteria and thus the need for all disciplines to work as a team. These are U.S. General Service Administration (GSA) principles or "hallmarks" for their workplace. (Figs. 1-3)

Fig. 1: A typical workstation layout involves corner orientation. Photo Credit: Haworth, from Better Lighting and Daylighting Solutions (2005, American Society of Interior Designers)

• Healthy: Create a clean, environmentally sustainable workspace with good acoustics, lighting, and air quality.
• Security and Safety: Create the workplace in such a way that physically protects the occupants and assets from man-made and natural hazards.
• Comfort: Distribute workplace services, systems, and components that allow occupants to adjust thermal, lighting, acoustics, and furniture systems to meet personal and group comfort levels.
• Reliability: Support the workplace with efficient, state-of-the-art heating, ventilating, air-conditioning (HVAC) systems, and equipment that require little maintenance, minimal loss of service, and less energy.
• Flexibility to address the client's goals are varied and can include:
  • Under floor access to all workspace services
  • Maximum user control of the work environment
  • Mobile furniture and technology
  • Building utilities that are everywhere, reconfigurable, and expandable
  • Alternate work places, hoteling, teleworking, etc.
  • Diverse work settings for diverse work and workforce
• Brand or Image: The work environment is one medium of communicating an organization's principles to internal and external customers. Branding creates a sense of pride and commitment to the organization and its stakeholders.
• Equity Fairness: The workspace is designed for function and provides all users with daylight, privacy, outside views, and personalized workspace in an aesthetically pleasing manner.
• Technological Connectivity: Enables full communication and simultaneous access to data among and distributed to coworkers both on and off-site including teleworking, hoteling, etc., and has built-in capacity and flexibility to adapt to future technologies.

D. Relationship of Interior Design to Involved Building Systems

Fig. 2: A more advantageous workstation layout includes office orientation and glazing. Photo Credit: Haworth, from Better Lighting and Daylighting Solutions (2005, American Society of Interior Designers)

Fig. 3: Design and lighting combine to create the visual environment as occupants perceive it. Photo Credit: Haworth, from Better Lighting and Daylighting Solutions (2005, American Society of Interior Designers)

The interior designer must not only be knowledgeable (though not an expert) in building systems, but also at times recommend a system concept that supports the goals of the client and the design direction. For example;

• Flexibility may be a key driver for the space. The interior designer may request that the engineers consider an under floor air distribution system with a raised floor solution to solve this problem. This impacts the architecture, electric, and data distribution.
• Lighting and equitable fairness may also be a driver. The interior designer in developing a scope of work for a lighting consultant must be aware of the coordination of daylight/views with electrical ambient light and individual task lights. This can impact the electrical engineer's work. In new construction, the interior designer may request that the window design accommodate equitable light distribution to all associates in the workplace.

It is important that the interior designer is included in these decisions and is given or develops with other disciplines the cost analysis and life-cycle costing to make the best design decision for the client. It is important to analyze building systems from a holistic viewpoint and specify environmentally sustainable materials and methods.

E. The Effects of Whole Building on the Interior Design Profession are Very Positive

• Requires recognition by the building industry that the interior design profession is critical in workplace problem solving.
• Creates more career opportunities for interior designers utilizing creative and business skills.
• Requires continuous education for the designer--both formal and informal.
• Requires awareness of the factors that exist that impact customer's organization: the global view, the business arena, demographics, technology, economics, changing nature of work, competition, etc.
• Creates need for interior design professionals to be knowledgeable in sustainable design and LEED accredited.
• Requires excellent communication skills to coordinate, collaborate, and guide the client, and contribute to the team's solutions. In some cases, the senior designer leads the effort.

Thus, an experienced designer has career opportunities as a strategic consultant, change agent, environmental expert, communication consultant, project manager, workplace researcher, writer, speaker, and brand consultant; in addition to doing the creative space planning and specifying finishes, materials, furniture, etc.

The benefits to the client can be enormous. The costs of projects can be reduced when all members are working from the beginning and coordinating information. Schedules can be tightened. This brings value to the client and accolades to the team.

Emerging Issues

Change is a given in the dynamic business arena, and interior design professionals must help clients adapt to change. Thus, the designer needs to be knowledgeable of the customer's business needs, competition, and values.

• Recent developments and research indicate a strong correlation between the quality of workplace design and worker productivity.
• Private sector corporations are using workplace design to attract and retain a talented, high performing workforce.
• Sustainable design and energy conservation is a goal for government agencies and others to reduce negative impact on the natural environment by the built environment. Sustainability is driving design decisions more frequently.
• The cost of moving associates is reduced with flexible work environments. It requires less work downtime, and reduces first cost.
• The consideration of life-cycle costing versus first-time costs can enhance user satisfaction, and reduce costs over the long term while providing a more productive work environment.
• Balancing the demographics of the workspace is challenging. Preparing for the departure of the baby boomers is daunting. Addressing the motivations and work habits of the new generation is critical. There are a minimum of four generations in the workforce with diverse motivations and drivers.
• Image and branding workspace expresses the principles of an organization and creates opportunities of dedication and connectivity of its associates. This is also a tool to attract and retain talent (e.g., cities are positioning to attract young professionals in order to revive the local brain trusts and economies).
• Population growth and education levels are rising faster in emerging economies than in established ones, thus shifting labor pools.
• Ease of mobility and other demographic forces are creating new worker demands for quality of life improvements that intelligent employers can leverage to attract and retain high performing employees. Telework, hoteling, and diverse work settings are now considered.
• Flattening the levels of an organization increases communication speed.
• Increased market competition is amplifying the need for and advantages of differentiation, innovation, and strategic direction. The workplace properly designed can increase and reward strategic and innovative ideas.

Ongoing issues will continue to impact the interior designer's performance and way of doing business.

• Technology will continue to impact the complexity and individualization of interior design education for both faculty and students.
• Every student will own a laptop computer and have advanced computer capabilities. Instructional delivery systems (e.g., Blackboard) will continue to expand the use of electronic research, multi-media presentations, and distance education.
• Design processes will integrate high-tech solutions and presentations for design projects and include virtual imaging and experiential spaces.
• Ongoing technological improvements will force education to partner with the professional community in cost sharing of high-tech equipment, software, and resources.

Relevant Codes and Standards

Professional Registration

Interior designers are regulated by title or licensed to practice in 25 U.S. states and jurisdictions: Alabama, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Illinois, Iowa, Kentucky, Louisiana, Maine, Maryland, Minnesota, Missouri, Nevada, New Jersey, New Mexico, New York, Puerto Rico, Tennessee, Texas, Virginia, Washington, DC, and Wisconsin. State regulations set qualifying standards of education, experience, and examination for the practice of interior design, and for the use of a state-designated title.

by Frances Mazarella, ASID, LEED AP, GSA Workplace Productivity Team / Jennifer Lipner, Associate Editor, American Society of Interior Designers

Updated: 

11-03-2016

New Method for Construction of Diaphragm Walls

Diaphragm walls are built to exclude earth and water from an area so that work may be performed under reasonably dry conditions. The range of applications for diaphragm walls includes earth-retaining and load-bearing walls for a variety of constructs such as underpasses, deep basements, underground stations, tunnels docks, and pump houses. In traditional construction methods, the concrete diaphragm wall consists of separate panels, which are not formed as a continuous monolithic construction. Vertical joints are used to divide the wall into panels, and horizontal reinforcement is not continuous from one panel to the next. Recently, a diaphragm wall, believed to be one of the largest ever built, was successfully constructed in Egypt with a continuous horizontal reinforcement. This paper describes in detail a new construction method for a diaphragm wall system. In addition, the difficulties encountered during construction are highlighted. Movements of the wall during excavation are reported. A comparison between the new and traditional construction methods is carried out in terms of cost and schedule. Applying the method presented in this paper offers substantial opportunity for reducing the steel reinforcement requirement and eliminating the use of shoring systems or ground anchors.

[New method of construction of artificial translational-coupled operons in bacterial chromosome].

The new method of translational-coupled operons construction in bacterial chromosome has been developed on the basis of recombineering approach. It includes construction in vitro of the artificial operon with efficiently translated proximal cistron followed by its insertion E. coli chromosome, modification of the operon due to Red-driven insertion of the special "Junction" with excisable selective marker in the intercistronic region of the initial operon and excising the marker. The structure of this Junction has been designed and tested in the present investigation. It consists of: 1) E. coli rplC-rplD intercistronic region for placing the TAA-codon of the proximal operon's gene in the SD-sequence (TAAGGAG) of rplD; 2) Cm(R)-gene flanked by lambdaattL/R-sites in such a fashion that after lambdaInt/Xis-driven excision of the marker the residual lambdaattB-site would not contain the termination codons in frame with ATG of rplD; 3) E. coli trpE-trpD intercistronic region for location of ATG of trpD at the position of initiation codon of the distal gene of original operon. The general design of desired construction provides the conversion of the original two-cistronic operon into three-cistronic operon with translational-coupled genes, where the coupling of the artificial ORF (rplD'-lambdaattB-'trpE) with the proximal gene is occurred due to rplC-rplD intercistronic region and the coupling of this ORF with the distal gene--due to trpE-trpD. The experimental implementation of the described strategy was showed by construction of artificial operon P(tac-aroG4-serA5, where expression optimization of the distal serA5 gene was achieved via construction of three-cistronic operon with translational-coupled genes.

brick bonds

ypes of Brick Bonds

Some of the different types of brick bonds are,

1. English bond,

2. Flemish bond,

3. Stretching bond,

4. Heading bond,

5. Garden wall bond,

6. Facing bond,

7. Raking bond,

8. Dutch bond,

9. English cross-bond,

10. Zig-Zag bond,

11. Silverlock’s bond.

English Bond

English bond consists of alternate course of headers and stretches. In this English bond arrangement, vertical joints in the header courses come over each other and the vertical joints in the stretcher course are also in the same line. For the breaking of vertical joints in the successive course it is essential to place queen closer, after the first header in each heading course. The following additional points should be noted in English bond construction:

(1) In English bond, a heading course should never start with a queen closer as it is liable to get displaced in this position.
(2) In the stretcher course, the stretchers should have a minimum lap of 1/4th their length over the headers.
(3) Walls having their thickness equal to an even number of half bricks, i.e., one brick thick wail, 2 brick thick wall, 3 brick thick wall and so on, present the same appearance on both the faces, i .e. a course consisting of headers on front face will show headers on the back face also.

Isometric view of  1½ brick wall in English bond is shown below,

(4) In walls having their thickness equal to an odd number of half brick, i.e. 1½ brick thick walls or 2½ brick thick walls and so on, the same course will show stretchers on one face and headers on the other.
(5) In thick walls the middle portion is entirely filled with header to prevent the formation of vertical joints in the body of the wall.
(6) Since the number of vertical joints in the header course is twice the number of joints in the stretcher course, the joints in the header course are made thinner than those in the stretcher course.

Flemish Bond – Types of Flemish Bond

In Flemish bond, each course consists of alternate headers and stretchers. The alternate headers of each course are centered over the stretchers in the course below. Every alternate course starts with a header at the corner. For the breaking of vertical joints in the successive courses, closers are inserted in alternate courses next to the quoin header. In walls having their thickness equal to odd number of half bricks, bats are essentially used to achieve the bond.

Flemish bond is further divided into two different types namely,
1. Single Flemish bond,

2. Double Flemish bond.

1. Single Flemish Bond.

This bond is a combination of English bond and Flemish bond.  In this work the facing of the wall consists of Flemish bond and the backing consists of English bond in each course. This type of bonding cannot be adopted in walls less than one and a half brick in thickness. This bond is adopted to present the attractive appearance of Flemish bond with an effort to ensure full strength in the brick work.

2. Double Flemish bond.

In Double Flemish Bond, each course presents the same appearance both in the front and back elevations. Every course consists of headers and stretchers laid alternately. This type of bond is best suited from considerations of economy and appearance. It enables the one brick wall to have flush  and uniform faces on both the sides. This type of bonding is comparatively weaker than English bond.

3. Stretching bond:

In this arrangement of bonding, all the bricks are laid as stretchers. The overlap, which is usually of half brick, is obtained by commencing each alternate course with a half brick bat. Stretching bond is used for half brick wall only. This bond is also termed as running bond and is commonly adopted in the construction of half brick thick leaves of cavity walls, partition walls, etc. Since there are no headers, suitable reinforcement should be used for structural bond.

4. Heading bond :

In this type of bonding all the bricks are laid as headers on the faces. The overlap, which is usually-of half the width of the brick is obtained by introducing a three-quarter bat in each alternate course at quoins. This bond permits better alignment and  as such it is used for walls curved on plan. This bond is chiefly used for footings in foundations for better transverse distribution of load.

5.Garden wall bond:

This type of bond is suitably adopted for one brick thick wall which may act as a garden wall or a boundary wall. In garden wall bond, it is possible to build uniform faces for a wall without much labour or expense. This type of bond is not so strong as English bond and its use is restricted to the construction of dwarf walls or other similar types of walls which are not subjected to large stresses. On accounts of its good appearance, this bond is sometimes used for the construction of the outer leaves of cavity walls.

There are two types of garden wall bond,
(a) English garden wall bond
(b) Flemish garden wall bond
(a) English garden wall bond. The general arrangement of bricks in this type of bonding is similar to that of English bond except that the heading courses are only inserted at every fourth or sixth course. Usually the arrangement consists of one course of headers to three courses of stretchers. A queen closer is placed next to the quoin header of the heading course to give the necessary lap.

(b) Flemish garden wall bond. This consists of alternate course composed of one header to three or sometimes even five stretchers in series throughout the length of the courses. Each alternate course contains a three quarter bat placed next to the quoin header and a header is laid over the middle of each central stretcher.

6.Facing bond:

This arrangement of bricks is adopted for thick walls, where the facing and backing are desired to be constructed with bricks of different thickness. This bond consists of heading and stretching courses so arranged that one heading course comes after several stretching courses. Since the number of joints in the backing and the facing differ greatly, the load distribution is not uniform. This may sometimes lead to unequal settlement of the two thickness of the wall.

7.Raking bond:

This is a bond in brick work in which the bonding bricks are laid at any angle other than zero or ninety degrees. This arrangement helps to increase the longitudinal stability of thick walls built in English bond. In this arrangement of bonding, the space between the external stretchers of a wall is filled with bricks inclined to the face of the wall. This bond is introduced at certain intervals along the height of a wall.

There arc two common forms of raking bond ;
(a) Herring hone bond
(b) Diagonal bond.

(a) Herring-bone bond. This type of bond is best suited for very thick walls usually not less than four bricks thick. In this arrangement of brick work, bricks are laid in course inclined at 45° in two directions from the centre. This bond is also commonly used for brick pavings.

(b) Diagonal bond. This bond is best suited for walls which are 2 to 4 brick thick. This bond is usually introduced at every fifth or seventh course along the height of the wall. In this bond, the bricks arc placed end to end in such a way that extreme corners of the series remain in contact with the stretchers.

8.Dutch bond:

This bond is a modification of the old English cross bond and consists of alternate courses of headers and stretchers. In this arrangement of brick work, each stretching course starts at the quoin with a three-quarter bat and every alternate stretching course has a header placed next to the three-quarter brick bat provided at the quoin.

9.English cross-bond:

This is similar to English bond and consists of alternate course of headers and stretchers. However, in this bond, queen closer are introduced next to quoin headers and each alternate stretching course has header placed next to quoin stretcher. This bond is sufficiently strong and bears a good elevation.

10. Zig-Zag bond:
This is similar to herring-bone bond with the only difference that in this case the bricks are laid in a zig-zag fashion. This is commonly adopted in brick paved flooring.

11. Silverlock’s bond:

This is a form of bonding brick-work in which bricks are laid on edge. It is economical but weak in strength and hence it is only recommended for garden walls or partition walls. In this bond, the bricks are laid as headers and stretchers in alternate courses in such a way that headers are laid on bed aid the stretchers are laid on edge forming a continuous cavity.

Fast Modern Construction Techniques by RBM

10 Innovations in Green Building Technology

 Build green or have an interest in building green? If so, take a look at 10 of the most innovative products—all nominees of the Best in IBS Awards at the NAHB International Builders’ Show—in green building technology today.
Big Ass Solutions – Haiku Designer Series LED fixture
The Haiku Designer Series LED fixture is designed to be an efficient, sleek and convenient for the consumer. It is so smart, that once it’s set up, it doesn’t even require the consumer to have a mobile app to guide its use. It’s composed of 144 energy-efficient LEDs, has a bank of sensors including motion, infrared, ambient light and temperature, and it’s offered in several different color options.
The newly trademarked Active Light Equalization technology adjusts the LEDs’ brightness automatically as the ambient light levels change to 16 different dimming settings. “When the sunlight pours in, our light will automatically dim down. Or you can schedule it to dim setting 5 and 2200K, which will help the body release melatonin for a good night’s sleep,” said Keith McKay, a business development manager for Big Ass Solutions. “Users can create customized lighting for any occasion — from amber to bright white.”
BASF – HP Wall Systems 
These innovative, structural insulated wall assemblies achieve up to R-34 in 2×4 construction, provide lateral bracing without OSB, save lumber while improving structural and energy performance, and help to simplify the construction process.
“The great thing about this system is that you can achieve 2×6 performance in a 2×4 construct,” said Chris Rosemond, a construction science architect with BASF. “These systems provide lighter weight, durable, long-lasting assemblies in a single-integrated system, which allow you to build stronger homes with less materials.”
According to the manufacturer, the HP+ E Series and HP+ X Series systems both exceed current codes in compressive strength, offer single plates with no direct load path required and can reduce lumber content by up to 25%. They also help improve moisture management, mitigating moisture-related losses, reduce condensation risk, and improve heating and cooling loads and associated utility usage.
Panasonic – SelectCycler Whole House Ventilation System
SelectCycler is a cost effective, whole ventilation solution for ASHRAE 62.2 compliance. By combining the best parts of both central fan integrated ventilation and exhaust fan ventilation, SelectCycler provides a high quality, energy-efficient ventilation solution. 
“Instead of using exhaust only, we can determine where the air comes from, which maximizes inbound and outbound air, and delivers fresh air throughout the home effectively and efficiently,” said Ken Nelson, northwest sales manager for the Panasonic eco products division.
The system is comprised of the WhisperGreen Select fan + Controller, FanConnect Wall Switch and Motorized Supply Damper.
Aquarius Brands – Retrax Solar Solutions
“There are four problems with solar,” said Howard Ullman, CEO of Atmospheric Water Solutions, the parent company of Aquarius Brands. “It’s expensive to install. Once it’s installed on a roof, we may need roof repair. Most home owners cannot install them on their own once they’re installed; and if you sell your house, you just left your solar.”
His solution: a preassembled, brand new patented3KW-5KW solar product that is easy to install and relocate. It comes folded up, pre-wired, and can be activated in less than 30 minutes. The panels can be transported by truck or aircraft, and no scaffolding is required.
  Alpha ProTech Engineered Products, Inc. – TECHNOply Synthetic Roof Underlayment
Danny Montgomery, senior vice president of manufacturing and engineered products for Alpha ProTech, recommends builders use TECHNOply Synthetic Roof Underlayment, a vertically integrated, polymer-based roofing material to replace traditional asphaltic felt papers.
“What makes it advanced is that it is manufactured and constructed from numerous types of polymers that are all polypropylene based,” he said. “We’re engaged in a full recycling program that allows us to incorporate scrap materials back into the manufacturing process without any detriment to the final product.”
As a result, TECHNOply brings no harmful VOCs or contaminates on the job site, outlasts asphalt-based products and answers the question of sustainability, he said.
Lennox – iComfort S30
The iComfort S30 is designed to help deliver the ultimate in home comfort by using geofencing monitoring technology.

“Do programmable thermostats save money? No. They’re difficult to program and most people don’t program them,” said Anubrav Rnajan, director of product management for Lennox International. “So we made it very simple for home owner with our smart away mode. It automatically adjusts the temperature based on whether or not you’re within the geofence.”
Additionally, the device measures outside temperature and humidity so that when a home owner sets it at 72 degrees, it actually feels like 72 degrees in the home. It also monitors air quality based on ZIP code, and automatically turns on the fan to clean the air.
Oikkos Group – Interior and Exterior Wall Finishes
These premier wall finishes, which feature natural binders with materials such as iron, concrete, Travertine, marble, ceramic, Corten steel, can be used in a variety of external and internal applications. They have no joints, are easily and inexpensively applied to standard walls, and the texture can be customized as desired.
Huber Engineered Woods – Zip Systems Sheathing and Tape
WINNER – Best of IBS Awards – Best Energy Efficient Product
The Zip System is a code approved, multifunctional building envelope solution with a weather resistive barrier that is combined into one product. Don Simon, education and training manager for Huber Engineered Woods, says that compared to traditional home building and what can often be a cumbersome process, the Zip System offers a unique, one-stop-shop solution that is easy to install and warranty.
  Outback Power Technologies, Inc. – FLEXpower Radian Grid/Hybrid System
In a world of grid-connected systems without storage (the vast majority of systems), a grid/hybrid with energy storage is the future perfect system, said Mark Cerasuolo, senior manager of marketing for Outback Power Technologies, Inc.
Outback’s power conversion for solar and other microgrid renewable energy systems is used around the globe to power hospitals, resorts, farms, military bases and anywhere electricity is needed. Now there’s a way to store that power for use anytime with the company’s newly launched FLEXpower Radian Grid/Hybrid energy storage technology, he said.
With the FLEXpower energy storage system, home owners can sell their surplus energy back to the grid (providing the utility company allows them to), which can help significantly reduce utility bills. Energy can be used whether the sun is shining or not, which is could mean great cost savings during times of the day when there is peak energy demand. With enough solar saved up, the home owner can effectively go off grid, Cerasuolo said.
“An ordinary grid-connected solar power system must disconnect from the grid per UL safety standards during an emergency. Without the grid, all that solar energy sits useless,” Cerasuolo said. “The FLEXpower system turns the home into a microgrid, so the homeowner can keep living comfortably without the use of a generator. They can use solar 24/7, at night, during outages and emergencies, and the utility companies benefit from more stable grid.”
NanaWall – SL80/81
“People love the NanaWall,” said Luke Mefford, national manager of the Residential Builders Program at NanaWall Systems, Inc. The company’s newest wall system is system engineered to be floor supported, eliminating the need to use steel, provides a U-Value of .21-.29, and can be customized in a wide variety of sizes and finishes, Mefford said.
The superior U-Values are achieved with a specially designed web of polyamide plastic reinforced with glass fibers thermal break in panel and frame profiles that are 3 1/8” thick, according to the manufacturer’s website.
“It maximizes the glass wall surface, but minimizes the frame surface,” Mefford said.
The multi-chamber profiles with 1 3/16” wide quadruple thermal insulation and cavities can accommodate either double or triple insulated glass, providing heat insulation that meets the latest European Energy saving regulations (EnEV).

Knowledge, Attitude, and Practice of Design for Safety: Multiple Stakeholders in the Singapore Construction Industry

This paper aims to investigate the design for safety (DfS) knowledge, attitude, and practice (KAP) of multiple stakeholders, including architects, civil and structural (CS) engineers, mechanical and electrical (ME) engineers, developers/clients, project managers, and safety professionals, and propose potential interventions to improve the DfS implementation in the construction industry. Data were collected from 257 multiple stakeholders in Singapore using a KAP questionnaire and seven semistructured interviews with DfS professionals, architects, developers, and project managers. The results indicated that the DfS knowledge level of survey participants needs to be improved. The majority of respondents demonstrated a positive attitude towards DfS, but the average level of DfS practice was low. Statistically significant differences in DfS practice were found between developers/clients, CS engineers, and project managers. Three recommendations for improving DfS implementation were proposed: (1) enhance DfS training programs, (2) establish a DfS Community of Practice, and (3) develop DfS courses in tertiary institutions. The findings of this paper can help in the design of strategies to improve the implementation of DfS in the construction industry at the national level and the approach can be used to track the effectiveness of DfS-related interventions across time.

Uncertainty-Aware Linear Schedule Optimization: A Space-Time Constraint-Satisfaction Approach

Schedules and physical workspaces are two key elements of linear construction projects that are extremely interdependent. Any negligence in incorporating spatial and temporal constraints in developing and improving schedules of linear projects results in inevitable delays and workspace congestions and can substantially hinder the performance of the activity resources. This study augments the current linear scheduling methods by presenting an uncertainty-aware optimization framework to optimize the duration of linear projects while minimizing their potential congestions. The methodology is built upon the new concept of space-time float for explicit consideration of spatio-temporal constraints of activities and their inherent uncertainty. A constraint satisfaction approach was used for the two-tier optimization of duration and congestion. A fuzzy inference system was also incorporated to assess the inherent uncertainty in the schedule. Two case examples from literature are analyzed. The results demonstrate the effectiveness of the proposed method in planning and control of the unforeseen variations from planned schedules of linear projects.

Dynamic Quality Control of Process Resource to Improve Concrete Supply Chain

The latest literature on quality management in the construction industry asserts that it has not been embraced as a holistic approach to improve overall performance. It is felt that management’s insistence on punch-list inspection creates barriers to adopting the model that fosters a culture of constant improvement embraced by total quality management (TQM). With this recognition, this research paper presents a model that extends the output-oriented process model to pursue continuous improvement along the supply chain. Extensive field observations and discussions with contractors show that the ready-mixed concrete supply and placement suffers the loss of information when concrete is delivered in truckloads and sampled for quality testing in the laboratory. Without recording the spatial boundaries of a truck volume of poured concrete, a failing quality report leads to large costs for core-drilling to find the location of the unacceptable concrete poured 28 days earlier. The latter part of the paper will present the work to design and field-experiment a feedforward control method that also served as a novel electronic as-built documenter. Ruggedized radio-frequency identification (RFID) tags were added (embedded) as the concrete flowed from the truck into the hopper of the pump. A hand-held RFID reader not only detected 14 out of the 15 embedded tags, but the tags’ readability served as an indicator of the concrete’s curing progress. The unique contribution of this research project can be seen in the experimental work established by the feasible evidence measured from a real-world construction context. In order to overcome the ingrained view of reactive inspection in concrete supply chains, this research offers a proposed approach whereby its workability is evaluated through first-hand examination.

Assessing Safety Risk among Different Construction Trades: Quantitative Approach

The construction industry has one of the worst occupational health and safety records of all industries. In recognition of this, several innovative safety techniques have been introduced to mitigate undesired events before they occur, including safety risk assessment. However, evaluation of safety risk is challenging due to the dynamic nature of the construction work environment and lack of reliable references. This study (1) compares safety risk of different construction trades in terms of common hazard types and sources of injuries, and (2) proposes safety risk quantification models by occupations, which can play a role as a safety reference for reliable safety risk assessment. Using occupational injury data, two relative injury indexes, relative fatality and relative days away injury indexes, were used to compare relative safety among 19 different construction occupations as well as the construction average. Each relative injury index of an occupation was further decomposed into hazard types, sources of injury, and injury scenarios. Based on comparative relative injury index data, a tree-based safety risk quantification model was proposed. The findings indicate each occupation has a unique pattern of safety data structure in terms of hazards and sources of injuries. In addition, the same occupation had different hazard types and sources of injury that can lead to different injury severities. A construction project typically involves numerous workers and resources. The safety risk analysis presented in this paper can be used as a general safety reference by safety managers to understand the dynamic nature of safety risk. It can also aid in preparing safety actions, such as inspections or training, more effectively by focusing on high-risk occupations, hazard types, or sources of injury. 

Investigating the Latent Factors of Quality of Work-Life Affecting Construction Craft Worker Job Satisfaction

Previous research in other disciplines identified that job satisfaction plays a major role in employee performance and retention. This paper examines the relationship between job satisfaction and quality of work-life (QWL) factors from the perspective of construction craft workers. The study analyzed data collected from 2002 to 2014 using the General Social Survey’s (GSS) QWL questionnaire module. Thirty-four of the 78 QWL variables were found to have a significant correlation with the overall level of job satisfaction of construction craft workers. By using the exploratory factor analysis, five latent factors—safety priority and organizational effectiveness, fair rewards system, resource adequacy, physical and mental health, and job tenure—were extracted. The relative impact of the five latent factors on construction craft worker job satisfaction also was identified. The paper contributes to the overall body of knowledge by identifying latent factors of QWL that affect craft worker job satisfaction specific to the construction industry. The findings of the paper can serve as guidance for construction companies to formulate policies and practices that contribute to better QWL, which can result in improved craft worker job satisfaction, leading to better retention and job performance.

How to inflate a huge hardened concrete shell

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of labor and material. A very resource efficient alternative construction method called "Pneumatic Forming of Hardened Concrete (PFHC)" was invented at TU Wien by Dr. Benjamin Kromoser and Prof. Johann Kollegger at the Institute of Structural Engineering. A simple air cushion and additional post-tensioning tendons transform a flat concrete plate into a double curved shell. Thus, the complicated spatially curved formwork and the framework are redundant. The Austrian Federal Railways Infrastructure (ÖBB Infrastruktur) are currently building a first test construction on a scale of 1:2 in Carinthia, in the south of Austria, which will later serve as event canopy.

The "Pneumatic forming of hardened concrete" construction method

The functioning of the construction method is comparatively easy: At first a flat concrete plate with wedge-shaped outlets is casted. After the concrete is hardened, the air cushion placed underneath the plate is inflated and the post-tensioning tendons at the circumference are tensioned until the final form is reached. Glass fiber reinforced plastic rods used as reinforcement absorb the occurring strains in the concrete plate. If the flat plate is produced with high accuracy, the construction method allows to build very precise concrete shells. The method also saves up to 50 percent of the concrete as well as 65 percent of the necessary reinforcement steel.

ÖBB test dome as event canopy

The test dome, built on behalf of the ÖBB Infrastruktur, has a length of 26.5 m, a width of 19.1 m and a height of 4.2 m. It will be used it to improve the construction technique for a first large application on a deer pass over the twin-track railway line "Koralmbahn" in 2017. Recently, the transformation process of the test dome was successfully finished, weighing 80 t and lifted with only 20-22 millibar from the flat plate to the spatially curved shell. The very smooth surface results from a sophisticated geometry optimization. "We could improve the construction method once again decisively during the preparation of the project for this first application," explains Dr. Benjamin Kromoser. In the next work steps, an additional concrete layer will be applied and some areas will be cut away. The final building can already be used for events in summer 2017.

Summary:

An alternative for resource intensive formwork for the construction of concrete domes has been developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure.

Finished concrete shell after the transformation process.

                   Credit: Image courtesy of Vienna University of Technology

STEEL FRAME STRUCTURES

Most steel construction is done with a type of steel called mild steel. Mild steel is a material that is immensely strong.  Take a circular bar of steel 1 inch / 25mm in diameter. If you were to attach this bar securely to your ceiling, you could hang from it 20,000 Kg (which is 20 tons), or any one of the following:

• 18 Honda City Cars
• 2 and a half African Elephants
• 1 and a half London City Routemaster Double-Decker Buses

We urge you to try this at home, unless you are married.

This immense strength is of great advantage to buildings.  The other important feature of steel framing is its flexibility.  It can bend without cracking, which is another great advantage, as a steel building can flex when it is pushed to one side by say, wind, or an earthquake.  The third characteristic of steel is its plasticity or ductility.  This means that when subjected to great force, it will not suddenly crack like glass, but slowly bend out of shape.  This property allows steel buildings to bend out of shape, or deform, thus giving warning to inhabitants to escape.  Failure in steel frames is not sudden - a steel structure rarely collapses.  Steel in most cases performs far better in earthquake than most other materials because of these properties.

However one important property of steel is that it quickly loses its strength in a fire. At 500 degrees celsius (930 degrees F), mild steel can lose almost half its strength. This is what happened at the collapse of the World Trade Towers in 2001. Therefore, steel in buildings must be protected from fire or high temperature; this is usually done by wrapping it with boards or spray-on material called fire protection.

where steel frame structures are used

Steel construction is most often used in 

• High rise buildings because of its strength, low weight, and speed of construction
• Industrial buildings because of its ability to create large span spaces at low cost
• Warehouse buildings for the same reason
• Residential buildings in a technique called light gauge steel construction
• Temporary Structures as these are quick to set up and remove

types of steel building construction

There are several types of steel building construction. Steel construction is also called steel fabrication.

Conventional Steel Fabrication is when teams of steel fabricators cut members of steel to the correct lengths, and then weld them together to make the final structure. This can be done entirely at the construction site, which is labour-intensive, or partially in a workshop, to provide better working conditions and reduce time.

Bolted Steel Construction occurs when steel fabricators produce finished and painted steel components, which are then shipped to the site and simply bolted in place. This is the preferred method of steel construction, as the bulk of the fabrication can be done in workshops, with the right machinery, lighting, and work conditions. The size of the components are governed by the size of the truck or trailer they are shipped in, usually with a max length of 6m (20ft) for normal trucks or 12m (40ft) for long trailers. Since the only work to be done at site is lifting the steel members into place (with cranes) and bolting, the work at site is tremendously fast. Pre-engineered buildings are an example of bolted steel construction that is designed, fabricated, shipped and erected by one company to the owner.

Light Gauge Steel Construction is a type of construction that is common for residential and small buildings in North America and parts of Europe. This is similar to wood framed construction, except that light gauge steel members are used in place of wood two-by-fours. Light gauge steel is steel that is in the form of thin (1-3mm) sheets of steel that have been bent into shape to form C-sections or Z-sections.

weight of steel frame structures

Consider a single storey building measuring 5 x 8m (16 x 26ft). Let us first construct this in concrete, with four columns at the corners, beams spanning between the columns, and a 150mm (6") thick concrete slab at the top. Such a structure would weigh about 800 kg/m2, or 32 Tons (32,000 kg) in total. If we build this of steel instead, with a sloping roof covered with corrugated metal sheeting with insulation, this would weigh only about 65 kg/m2. The steel framed building will weigh only 2.6 Tons (2,600 kg). So the concrete building is over 12 times heavier! This is for single storey structures - in multi-storey structures, the difference will be less, as the floors in multi-storey steel buildings are built of concrete slabs for economy - but the difference is still significant. 

This low weight of steel frame buildings means that they have to be firmly bolted to the foundations to resist wind forces, else they could be blown away like deck umbrellas!

advantages of steel structures

Steel structures have the following advantages:

• They are super-quick to build at site, as a lot of work can be pre-fabbed at the factory.
• They are flexible, which makes them very good at resisting dynamic (changing) forces such as wind or earthquake forces.
• A wide range of ready-made structural sections are available, such as I, C, and angle sections
• They can be made to take any kind of shape, and clad with any type of material
• A wide range of joining methods is available, such as bolting, welding, and riveting

disadvantages of steel structures

Steel structures have the following disadvantages:

• They lose strength at high temperatures, and are susceptible to fire.
• They are prone to corrosion in humid or marine environments.

concrete frame structures load bearing masonry

steel frame structures light gauge steel

wood framed structures pre engineered buildings