Analyses and tests to determine the effective widths of composite beams in unbraced multistorey frames

1986 ◽  
Vol 13 (1) ◽  
pp. 66-75 ◽  
Author(s):  
E. H. Fahmy ◽  
Hugh Robinson
Keyword(s):  
Concrete Slab ◽  
Concrete Strength ◽  
Composite Beams ◽  
Steel Frame ◽  
Slab Width ◽  
Lateral Forces ◽  
Measured Strain ◽  
Ultimate Moment ◽  
Strength And Stiffness ◽  
Good Agreement

This paper concerns the analysis and testing of 10 cantilever composite beams incorporating ribbed metal deck, representing the positive moment beam–column connections in an unbraced steel frame with composite floor beams. The positive moment beam–column connections arise from lateral forces on the unbraced frame. The effective widths of the slabs for strength and stiffness calculations have been determined from analysis. Agreement between the calculated strain distributions across the concrete slab width and the corresponding measured strain distributions was attained. Use of the calculated effective widths of the slab for strength together with a concrete strength of [Formula: see text] gave good agreement with the measured positive ultimate moment capacities of the cantilever composite beams subjected to upward end test loads.

Analysis of Long-Term Stress of Steel-Concrete Composite Beams

2010 ◽  
Vol 163-167 ◽  
pp. 2037-2040
Author(s):  
Min Ding ◽  
Jin San Ju ◽  
Xiu Gen Jiang
Keyword(s):  
Relative Humidity ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Composite Beams ◽  
Reinforcement Ratio ◽  
Longitudinal Reinforcement ◽  
Slab Width ◽  
Yearly Average ◽  
Average Relative Humidity

The theoretical model to compute long-term stress of steel-concrete composite beam was deduced. On this basis, the effects of factors such as concrete age to loading, longitudinal reinforcement ratio in concrete slab, concrete slab width, environmental yearly average relative humidity and concrete strength on long-term stress of composite beams are discussed. The results show that additional stress at the top of concrete slab is tensile stress and that at the bottom of steel beam is compressive stress. Concrete slab width, as well as longitudinal reinforcement ratio can not be ignored. Concrete strength and concrete age to loading have relatively bigger effect as well. But environmental yearly average relative humidity has less impact.

scholarly journals Longitudinal shear capacity of the slabs of composite beams

1976 ◽  
Vol 3 (4) ◽  
pp. 514-522 ◽  
Author(s):  
M. N. El-Ghazzi ◽  
H. Robinson ◽  
I. A. S. Elkholy
Keyword(s):  
Composite Beam ◽  
Shear Failure ◽  
Concrete Slab ◽  
Compressive Force ◽  
Longitudinal Shear ◽  
Composite Beams ◽  
Shear Capacity ◽  
Slab Width ◽  
Two Parameters ◽  
Concrete Elements

The longitudinal shear failure of the slab of composite beams is constrained to occur at a predetermined shear surface. A method for calculating the longitudinal shear capacity of the slab of simply-supported steel–concrete composite beams is presented. The method is based on analyzing the stresses at failure of the concrete elements located at the slab shear surface.A design chart based on estimating the transverse normal stress required within the concrete slab to achieve the full ultimate flexural capacity of the composite beam is proposed. Alternatively, using elastic–plastic stress distribution across the concrete slab, the longitudinal compressive force due to bending and hence the applied moment can be predicted for any longitudinal shear capacity of the slab. The proposed design and analysis when compared to previous tests and analysis showed good agreement.The slab width and the shear span of the composite beam are found to be two important parameters which cannot be neglected when estimating the longitudinal shear capacity of the slab. These two parameters have been neglected in the empirical solutions previously adopted.

scholarly journals Investigation of the Mechanical Behavior of Partially Precast Partially Encased Assembled Composite Beams

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Liufeng Zhang ◽  
Yinghua Yang
Keyword(s):  
Mechanical Properties ◽  
Composite Beam ◽  
Low Cost ◽  
Concrete Strength ◽  
Composite Beams ◽  
Test Results ◽  
Structural Form ◽  
Heavy Load ◽  
Grade Steel ◽  
Good Agreement

In view of the characteristics of a high floor and the heavy load of logistics buildings, a partially prefabricated partially encased assembled composite beam (PPEC) is proposed in order to achieve the low cost construction of such buildings. In this research, the mechanical properties of PPEC beams were studied experimentally. The effects of the concrete strength grade, steel content, shear span ratio, and fabrication methods on the mechanical properties of the PPEC beams were analyzed. The results showed that the proposed structural form of the PPEC beams was generally feasible. Based on the test results, a practical shear formula for PPEC beams was proposed, and the calculated results were in good agreement with the test results.

Shear stiffness of inclined screws in timber–concrete composite beam with timber board interlayer

2020 ◽  
Vol 23 (16) ◽  
pp. 3555-3565
Author(s):  
Hao Du ◽  
Xiamin Hu ◽  
Zhixiang Sun ◽  
Weijie Fu
Keyword(s):  
Calculation Method ◽  
Composite Structures ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Shear Stiffness ◽  
Composite Beams ◽  
Embedment Depth ◽  
Practical Applications ◽  
Screw Diameter ◽  
Timber Board

The timber board interlayer is applied as the formwork for the pouring of concrete slab in various practical applications of timber–concrete composite structures, with the rehabilitation of timber buildings, in particular. At present, there are few studies performed to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. In this article, eight groups of shear tests were carried out to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. The key parameters included the embedment depth of the screw connector into timber, screw diameter, the thickness of concrete slab, and concrete strength. As indicated by the test results, the shear stiffness of the inclined screws was improved as the embedment depth of screw into timber and screw diameter increased. When the embedded depth of screw into concrete remained unchanged, the thickness of concrete slab and concrete strength exhibited no significant impact on the shear stiffness of inclined crossing screws. On the basis of the theory of a beam on a two-dimensional elastic foundation, the calculation method for predicting the shear stiffness of inclined screw in timber–concrete composite beams with interlayer was proposed. The comparisons demonstrated that the shear stiffness of inclined screw can be well predicted using the calculation method.

scholarly journals Effective Flange Width for Composite Steel Beams

2011 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
T. Salama ◽  
H.H. Nassif
Keyword(s):  
Concrete Slab ◽  
Composite Beams ◽  
Analytical Investigation ◽  
Steel Beams ◽  
Limit States ◽  
Composite Action ◽  
Shear Connectors ◽  
Slab Width ◽  
Effective Flange Width ◽  
Composite Steel

 The effective flange width is a concept proposed by various codes to simplify the computation of stress distribution across the width of composite beams. Questions have been raised as to the validity of the effective slab width provisions, since they have a direct effect on the computed ultimate moment as well as serviceability limit states such as deflection, fatigue, and overloading. The objective of this paper is to present results from an experimental and analytical investigation to determine the effective slab width in steel composite beams. The Finite Element Method (FEM) was employed for the analysis of composite steel-concrete beams having variable concrete flange widths. Results were compared to those from tests performed on eight beams loaded to failure. Beam test specimens had variable flange width and various degrees of composite action (shear connectors). The comparison presented in terms of the applied load versus deflection, and strain in the concrete slab show that the AISC-LRFD code is conservative and underestimates the width active. Based on a detailed parametric study an equation for the calculation of the effective flange width is recommended. 

Longitudinal cracking of composite beams with ribbed metal deck

1986 ◽  
Vol 13 (6) ◽  
pp. 733-740 ◽  
Author(s):  
M. S. Elkelish ◽  
Hugh Robinson
Keyword(s):  
Analytical Study ◽  
Concrete Slab ◽  
Single Point ◽  
Longitudinal Crack ◽  
Composite Beams ◽  
Point Load ◽  
Width Ratio ◽  
Slab Width ◽  
Longitudinal Cracking ◽  
Solid Part

An analytical study of the longitudinal cracking of composite beams with ribbed concrete slab on metal deck is presented. A layered finite element is used to model the composite beam in the analysis. The influence of six parameters on the development of the longitudinal crack is investigated in this study. These parameters are type of loading, compressive strength of the concrete slab, beam span to slab width ratio, thickness of the solid part of the slab, percentage of transverse reinforcement, and the existence of the metal deck. Three types of loading are considered, namely, uniformly distributed load over the entire slab area, single point load applied at mid-span of the beam, and two point loads applied at the third points of the span. The type of loading of composite beams has a significant effect on the location of the initial longitudinal crack.

scholarly journals Finite Element Analysis on Shear Behavior of High-Strength Bolted Connectors under Inverse Push-Off Loading

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 479
Author(s):  
Wei Wang ◽  
Xie-dong Zhang ◽  
Fa-xing Ding ◽  
Xi-long Zhou
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Three Dimensional ◽  
High Strength ◽  
Element Model ◽  
Composite Beams ◽  
Element Analysis ◽  
Shear Connectors ◽  
Parametric Analyses

High-strength bolted shear connectors (HSBSCs), which can be demounted easily and efficiently during deconstruction, are recommended to replace the conventional steel studs in steel–concrete composite beams (SCCBs) to meet the requirements of sustainable development. The existing investigations on the behavior of HSBSCs mainly focus on the positive moment area of composite beams, in which the concrete slab is in compress condition. In this paper, a three-dimensional finite element model (FEM) was developed to investigate the performance of HSBSCs subjected to inverse push-off loading. Material nonlinearities and the interactions among all components were included in the FEM. The accuracy and reliability of the proposed FEM were initially validated against the available push-off test results. Load-carrying capacity and load–slip response of the HSBSCs under inverse push-off loading were further studied by the verified FEM. A parametric study was carried out to determine the influence of the concrete strength, the diameter and tensile strength of bolt and the clearance between the concrete slab and the bolt as well as the bolt pretension on the shear performance of HSBSCs. Based on the extensive parametric analyses, design recommendations for estimating the shear load at the first slip and load-bearing resistance of HSBSCs were proposed and verified.

Effective widths of composite beams with ribbed metal deck

1986 ◽  
Vol 13 (5) ◽  
pp. 575-582 ◽  
Author(s):  
S. Elkelish ◽  
Hugh Robinson
Keyword(s):  
Compressive Strength ◽  
Composite Beam ◽  
Ultimate Load ◽  
Concrete Slab ◽  
Composite Beams ◽  
Analytical Investigation ◽  
Steel Beam ◽  
Effective Width ◽  
Slab Width ◽  
Service Load

The effective width of the concrete slab of a composite beam is used in the determination of its moment resistance and service load moment for the purposes of structural design of the composite beam. It is usually assumed that the same effective width of the concrete slab may be used for both ultimate strength and elastic stage calculations.This paper presents the results of an analytical investigation of the variation of the effective width of composite beams and ribbed slabs formed by ribbed metal deck in both the elastic and inelastic stages and at ultimate load. A layered finite element method is used to model the composite beam. The influence of four variables on the effective width of the composite beams was studied, namely, type of loading, beam span to actual concrete slab width, ultimate compressive strength of the concrete, and steel beam size.It was found that the effect of the compressive strength of the concrete and the size of the steel beam have negligible influence on the effective width of the concrete slab. The effective width of the slab at ultimate load is of the order of 4% larger than that in the elastic range.The effective width used for the design of composite beams under a uniformly distributed load, which is the practical loading in most cases, is significantly different from that which should be used for any other type of loading.

Theoretical and experimental research on slip and uplift of the timber-concrete composite beam

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7079-7099
Author(s):  
Jianying Chen ◽  
Guojing He ◽  
Xiaodong (Alice) Wang ◽  
Jiejun Wang ◽  
Jin Yi ◽  
...  
Keyword(s):  
Differential Equations ◽  
Deformation Theory ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Structural Element ◽  
Structural Efficiency ◽  
Theoretical Investigations ◽  
New Type ◽  
Interlayer Slip ◽  
Good Agreement

Timber-concrete composite beams are a new type of structural element that is environmentally friendly. The structural efficiency of this kind of beam highly depends on the stiffness of the interlayer connection. The structural efficiency of the composite was evaluated by experimental and theoretical investigations performed on the relative horizontal slip and vertical uplift along the interlayer between composite’s timber and concrete slab. Differential equations were established based on a theoretical analysis of combination effects of interlayer slip and vertical uplift, by using deformation theory of elastics. Subsequently, the differential equations were solved and the magnitude of uplift force at the interlayer was obtained. It was concluded that the theoretical calculations were in good agreement with the results of experimentation.

The Influence of Slab Concreting Sequence on a Continuous Composite Girder Bridge

2016 ◽  
Vol 691 ◽  
pp. 96-107
Author(s):  
Tomas J. Zivner ◽  
Rudolf B. Aroch ◽  
Michal M. Fabry
Keyword(s):  
Concrete Slab ◽  
Transverse Cross Section ◽  
Slab Thickness ◽  
Slab Width ◽  
Composite Girder ◽  
Steel Members ◽  
Composite Bridge ◽  
Bridge Girder ◽  
Girder Bridge ◽  
Main Girder

This paper deals with the slab concreting sequence and its influence on a composite steel and concrete continuous highway girder bridge. The bridge has a symmetrical composite two-girder structure with three spans of 60 m, 80 m, 60 m (i.e. a total length between abutments of 200.0 m). The horizontal alignment is straight. The top face of the deck is flat. The bridge is straight. The transverse cross-section of the slab is symmetrical with respect to the axis of the bridge. The total slab width is 12 m. The slab thickness varies from 0.4 m on main girders to 0.25 m at its free edges and 0.3075 m at its axis of symmetry. The center-to-center spacing between main girders is 7 m and the slab cantilever on either side is 2.5 m long. Every main girder has a constant depth of 2800 mm and the thicknesses of the upper and lower flanges are variable. The lower flange is 1200 mm wide whereas the upper flange is 1000 mm wide. The two main girders have transverse bracing at abutments and at internal supports and at regular intervals in every span. The material of concrete slab is C35/45 and of steel members S355. The on-site pouring of the concrete slab segments is performed by casting them in a selected order and is done after the launching of the steel two girder bridge. The paper presents several concreting sequences and their influence on the normal stresses and deflections of the composite bridge girder.

Sign in / Sign up

Export Citation Format

Share Document