COFFER SLAB AND BEAM DESIGN

COFFER SLAB AND BEAM DESIGN 

Nowadays, in the construction field, there are tremendous new technology and techniques used to give a decent look to the building so that the people get attracted to the buildings and it will give the dealers and buyers to get through it. In this modern organization, the people demand that they have an innovative and creative design of the building for the aesthetic point of view. This paper represents that in the commercial building for the architectural consultant to design and shape by the coffer slab with different types of molds used as per the drawings that are required by the client perspective and overview.

About The Author:

Sp.Aswinpalaniappan.,DCE.,B.E., M.E.,(Structural)

Slab Length	8.56	m
Slab Width	16.17	m
Thickness of slab	0.10	m
Concrete Grade	M25	N/Sq.mm
Concrete Grade	25	N/Sq.mm
steel Grade	Fe500	N/Sq.mm
steel Grade	500	N/Sq.mm
Spacing of Rib (s)	1	m
Dimension of Slab & Beam
Depth	0.428	m
D	450	mm
Width of Rib	200	mm
1. Load Calculation
Weigt of Slab	2.50	Kn
Total Load of slab	346.04	Kn/m
Weight of Rib	1.75	Kn
Total Load of Beam in X-Direction	104.86	Kn/m
Total Load of Beam in y-Direction	424.46	Kn/m
Total Weight of Floor Finish	207.62	Kn/m
Total Weight of Live load	0.00	Kn/m
Total Load(W)	1082.98	Kn/m
Load per Sq.m(q)	7.82	Kn/Sq.m
2. Approximate Method(Moment)
q1	7.25	Kn/Sq.m
q2	0.57	Kn/Sq.m
moments in x & y direction @ center of grid for 1.0 width taken as
Mx	66.44	Kn.M
My	18.62	Kn.M
Qx	31.05	Kn
Qy	4.61	Kn
The approximate method neglect the twisting moment in the grid
maximum working moment	66.44	Kn.M
moment resisted by central rib in x-direction over 1.0m width	66.445	Kn.M
Ultimate moment	99.67	Kn.M
Muf	331200000000.0
	331.85*10^6	Kn.M
Since Mu lessthan Muf
Neutral axis fall within the flange
	811.391	Sq.mm
provided 4 bars of 20mm diameter (Ast=1255Sq.mm)
maximum working moment	18.62
moment resisted by central rib in y-direction over 1.0m width	18.62
Ultimate moment	27.93
	227.383	Sq.mm
provided 2 bars of 16mm diameter (Ast=402Sq.mm
maximum ultimate shear	6.91	Kn
Tv	0.07	N/sq.mm
Assuming two bars to be bent up near support	982	Sq.mm
100ast/bd	1.09
Tc	0.62	N/sq.mm

Grid U-Wrap Anchorage for Reinforced Concrete Beams Strengthened with Carbon Fiber-Reinforced Polymer Sheets

Grid U-Wrap Anchorage for Reinforced Concrete Beams Strengthened with Carbon Fiber-Reinforced Polymer Sheets

Abstract:

This paper presents the feasibility and effectiveness of an alternative anchor system for reinforced concrete beams strengthened with carbon fiber-reinforced polymer (CFRP) sheets. Continuum U-wrap anchors that enclose the longitudinal CFRP sheets are conventionally employed to impede the premature delamination of the sheets. This method, however, is not cost-effective and completely blocks the bonded region, thereby disrupting any technical maintenance and visual inspections on the shear span of the beam. Grid CFRP U-wraps are proposed to address these concerns. Twenty beams are tested to examine the effects of the following parameters: anchorage types (continuum and grid U-wraps), grid configurations, shear-span coverage ratios (25 to 100%), bonding schemes (epoxy and silyl-modified polymer [SMP] adhesives), and loading conditions (monotonic and cyclic). Of interest are the flexural capacity of the strengthened beams, failure modes and crack propagation, and strain development that represents the behavior of the CFRP-concrete interface. The grid U-wraps alter the failure characteristics of the beams in conjunction with the interrupted formation of diagonal tension cracks. The use of SMP alleviates stress concentrations at the beam corners, preserving the integrity of the grid U-wraps. Cyclic loading brings about the progressive shearing of the CFRP sheet; accordingly, the capacity of the strengthened beams decreases. When SMP-epoxy hybrid bonding is used, the grid U-wraps result in flexural responses comparable with those of their continuum counterparts. Statistical inference techniques clarify the relationship between the anchorage configuration and the coverage ratio.

Thanks to 

Author(s): Yail J. Kim and Mohammed Bhiri

Publication: Structural Journal

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