scholarly journals Enhancement of Shear Transfer in Composite Deck with Mechanical Fasteners

2018 ◽  
Author(s):  
Christopher McComb ◽  
Fariborz Tehrani
Keyword(s):  
Concrete Slab ◽  
Steel Beams ◽  
Initial Stiffness ◽  
Additional Increase ◽  
Shear Transfer ◽  
Composite Action ◽  
Construction Methods ◽  
Reinforcing Fibers ◽  
Floor Systems ◽  
Steel Deck

Reinforced concrete construction and steel construction are two of the most common contemporary construction methods. Both methods make use of composite decks as floor systems and diaphragms. During the design of composite decks, the interaction between the steel deck and concrete slab is typically disregarded when calculating the strength of the composite di- aphragm due to lack of complete shear transfer, as existing practices such as stamping are not effective to provide substantial composite action. This conservative assumption essentially results in non-efficient use of material. This paper presents a method for ensuring shear transfer through the use of conventional sheet metal screws, driven through the corrugated steel deck and embedded in the fresh concrete. This method is proposed for use in the field between formed steel beams. Both experimental and analytical stud- ies support an increase in strength with the addition of embedded fasteners. Further, experimental results indicate an additional increase in strength with the addition of synthetic reinforcing fibers. The increase in strength with the addition of the fasteners is on the order of 100%. When fasteners are already in use, the addition of synthetic reinforcing fibers can increase strength on the order of 10%. The ultimate deflection of enhanced deck is comparable to deck tested without fasteners, but the initial stiffness of enhanced deck is much higher.

scholarly journals Enhancement of Concrete Composite Decks

2018 ◽  
Author(s):  
Christopher McComb
Keyword(s):  
Reinforced Concrete ◽  
Sheet Metal ◽  
Concrete Construction ◽  
Shear Transfer ◽  
Work Support ◽  
Construction Methods ◽  
Analytical Work ◽  
Reinforcing Fibers ◽  
Floor Systems ◽  
Steel Deck

Reinforced concrete construction and steel construction are two of the most common contemporary construction methods. Both methods make use of composite decks as floor systems and diaphragms. During the design of composite decks, the steel deck is typically disregarded when calculating the strength of the slab since shear transfer can’t be ensured. This essentially results in efficient use of material. This report presents a method for ensuring shear transfer through the use of typical sheet metal screws, driven through the corrugated steel deck and embedded in the concrete. Both experimental and analytical work support an increase in strength with the addition of embedded fasteners, and an increase in strength with the addition of synthetic reinforcing fibers.

scholarly journals Semi-continous beam-to-column joints for slim-floor systems in seismic zones

2018 ◽  
Author(s):  
Adrian Ciutina ◽  
Cristian Vulcu ◽  
Rafaela Don
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Bending Moment ◽  
Steel Structures ◽  
Bending Test ◽  
Steel Beams ◽  
Element Analysis ◽  
Natural Fire ◽  
Floor Systems ◽  
Moment Resisting

The slim-floor building system is attractive to constructors and architects due to the integration of steel beam in the overall height of the floor, which leads to additional floor-to-floor space, used mostly in acquiring additional storeys. The concrete slab offers natural fire protection for steel beams, while the use of novel corrugated steel sheeting reduces the concrete volume, and replaces the secondary beams (for usual spans of steel structures). Currently the slim-floor solutions are applied in non-seismic regions, and there are few studies that consider continuous or semi-continuous fixing of slim-floor beams. The present study was performed with the aim to develop reliable end-plate bolted connections for slim-floor beams, capable of being applicable to buildings located in areas with seismic hazard. It is based on numerical finite element analysis, developed in two stages. In a first stage, a finite element numerical model was calibrated based on a four point bending test of a slim-floor beam. Further, a case study was analysed for the investigation of beam-to-column joints with moment resisting connections between slim-floor beams and columns. The response was investigated considering both sagging and hogging bending moment. The results are analysed in terms of moment-rotation curve characteristics and failure mechanism. 

A study on influencing factors for simplified seismic collapse risk assessment of steel moment-resisting frames with intermediate ductility

2019 ◽  
Vol 11 (6) ◽  
pp. 833-848
Author(s):  
Sassan Eshghi ◽  
Mohammad Mahdi Maddah
Keyword(s):  
Risk Assessment ◽  
Concrete Slab ◽  
Assessment Process ◽  
Steel Beams ◽  
Collapse Mechanism ◽  
Content Type ◽  
Steel Moment Resisting Frames ◽  
Composite Action ◽  
Seismic Collapse ◽  
Steel Mrfs

Purpose Mid-rise steel moment-resisting frames (MRFs) with intermediate ductility are a major part of conventional residential buildings in Iran. According to Iranian seismic design codes, in this resisting system, considering the strong-column/weak-beam (SCWB) criterion is not mandatory. Where a metal deck ceiling system is used, the composite action of a concrete slab and steel beams could change the collapse mechanism of the structure, especially in the MRFs with intermediate ductility. The purpose of this paper is to investigate the influence of the composite action in the seismic collapse risk of this type of structures. Seismic collapse risk assessment can be carried out by using simplified pushover-based methods. In these methods, the cyclic deterioration of an equivalent single degree of freedom (ESDoF) system must be considered when the modified Ibarra–Medina–Krawinkler is used for nonlinear modeling of MRFs. Accordingly, a modified method is developed to use in simplified collapse risk assessment process. For these purposes, two mid-rise MRFs with intermediate ductility located in Tehran have been selected as case studies. The results confirm that the composite action is very effective in collapse risk value in the steel MRFs in which their SCWB ratio is less than 1. Moreover, the proposed approach of considering the cyclic deterioration of ESDoF systems increases the accuracy of the simplified collapse assessment approaches. Design/methodology/approach Identifying seismically vulnerable buildings to collapse requires using robust methods. These methods can be simplified based on pushover analysis methods. An attempt was made to apply one of these approaches for steel MRFs with intermediate ductility. In these frames, the composite action of a concrete slab and steel beams could change the collapse mechanism. Here, two MRFs were investigated in order to assess this effect on collapse risk value. This process was done by modifying the SPO2IDA method as a simplified collapse capacity evaluation approach by developing a relationship to consider the cyclic deterioration effects for the ESDoF systems. Findings The results showed that it is necessary to consider the slab effects in the analytical model in the collapse assessment process of MRFs with intermediate ductility, especially in the condition in which the SCWB ratios of the frame are less than 1. Furthermore, by utilizing the proposed method of considering the ESDoF cyclic deterioration, the error values of the SPO2IDA program were reduced significantly. Moreover, estimating the collapse risk parameters shows that the utilized simplified method presents suitable accuracy and could be an acceptable approach to collapse risk assessment of mid-rise steel MRFs. Originality/value The influence of the composite action in seismic collapse risk of MRFs with intermediate ductility is investigated. Also, a modified relationship is developed to consider the deterioration effects on the ESDoF parameters used in simplified collapse risk assessment process. Also, a framework is presented for utilized methodology.

Tests of composite beams with web holes

1983 ◽  
Vol 10 (4) ◽  
pp. 713-721 ◽  
Author(s):  
R. G. Redwood ◽  
G. Poumbouras
Keyword(s):  
Composite Beam ◽  
Concrete Slab ◽  
Composite Beams ◽  
Web Openings ◽  
Composite Action ◽  
Shear Connection ◽  
Moment Ratio ◽  
Construction Loads ◽  
Steel Deck ◽  
Steel Section

Tests of composite beams comprising a concrete slab supported on a steel deck and a steel wide-flange shape containing large web openings are described. Special attention is directed to the amount of shear connection between slab and steel section in the region of a web hole, and on the effect of construction loads acting on the steel section prior to composite action being effective.It is shown that limited shear connection at the hole will significantly affect the strength when loading produces a high shear-to-moment ratio, and a theory is presented which conservatively takes this into account. The effect of construction loads on unshored construction is shown to be small when these do not exceed 60% of the non-composite beam resistance at the hole.

Évaluation expérimentale et renforcement des ponts en acier avec dalle de béton non participante

1994 ◽  
Vol 21 (2) ◽  
pp. 329-339
Author(s):  
G. Dionne ◽  
D. Beaulieu ◽  
A. Picard
Keyword(s):  
Experimental Study ◽  
Key Words ◽  
Experimental Work ◽  
Concrete Slab ◽  
Steel Beams ◽  
Flexural Stiffness ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Composite Action ◽  
Slender Beams

An experimental study was carried out to assess the stabilizing action of the friction between concrete slab and steel beams in noncomposite constructions. Slender beams, sensitive to lateral torsional buckling, were used in the experimental work. The results show that the friction is sufficient to prevent lateral torsional buckling of the steel beams. However, the flexural stiffness was not significantly increased so that friction alone is not sufficient to develop a composite action. To increase the frictional effect, the concrete slab was linked to the steel beams by two types of connectors. Additional tests were carried out to verify the efficiency of these connectors. Key words: steel bridges, lateral torsional buckling, composite action friction, reinforcement.

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. 

Composite Action Between Cold-Formed Steel Beams and Wood-Based Floorboards

2015 ◽  
Vol 15 (08) ◽  
pp. 1540029 ◽  
Author(s):  
Pinelopi Kyvelou ◽  
Leroy Gardner ◽  
David A. Nethercot
Keyword(s):  
Steel Beams ◽  
Bending Tests ◽  
Shear Transfer ◽  
Composite Action ◽  
Four Point Bending ◽  
Bending Capacity ◽  
Cold Formed Steel ◽  
Structural Adhesive ◽  
Transfer Mechanisms ◽  
Material Tests

An experimental investigation has been conducted into the degree of shear interaction between cold-formed steel floor joists and wood-based flooring panels and the resulting benefits derived in terms of composite action. A series of four-point bending tests have been carried out to evaluate the overall system behavior, while material tests have been performed to accurately define the material properties of each component of the examined system. Two different shear transfer mechanisms were examined: self-drilling screws with varying spacing and structural adhesive. The bare system was also tested to provide a reference response, against which the stiffness and capacity of the composite system could be bench-marked. The experiments showed that significant benefit could be derived as a result of composite action with as much as a 100% increase in bending capacity and 42% increase in stiffness.

scholarly journals Behavior of Steel- Lightweight Concrete Composite Beams with Partial Shear Interaction

2018 ◽  
Vol 26 (2) ◽  
pp. 20-34
Author(s):  
Fareed Hameed Majeed
Keyword(s):  
Lightweight Concrete ◽  
Concrete Slab ◽  
Composite Beams ◽  
Point Load ◽  
Steel Beams ◽  
Initial Stiffness ◽  
Normal Concrete ◽  
Simply Supported ◽  
Modes Of Failure ◽  
Analysis Theory

This experimental work along with an analyticalanalysis is investigated.The behavior of simply supported steel beams with lightweight and normal concrete slab that have the same compressive strengthand slump was studied. Eight specimens tested under mid-point load and analysis by plastic analysis theory. Four of composite beams havea steel I-section beam with normal concreteslab and the other four with lightweight concrete slab. Different degrees of shear interaction were considered (100% to 40%). It was observed that there are no essential differences between the modes of failure that appeared in the tested composite beams with normal and lightweight concrete. Also, it was notedthat there is a decrease in the initial stiffness and also in the ultimate strength of the composite beams when the concrete of the flanges for the tested specimens was replaced from normal to lightweight concrete for different degrees of shear connections.The analytical results for all tested beam specimens, except that with normal concrete and 100% degree of shear interaction, gave overestimate results compared with those of experimental results.

scholarly journals Design for Deconstruction for Sustainable Composite Steel-Concrete Floor Systems

2018 ◽  
Author(s):  
Jerome F. Hajjar ◽  
Lizhong Wang ◽  
Mark D. Webster
Keyword(s):  
Raw Materials ◽  
Precast Concrete ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Concrete Slabs ◽  
Steel Beams ◽  
Design Strategies ◽  
Composite Action ◽  
Floor Systems ◽  
Headed Stud

Conventional steel-concrete composite floor systems utilizing steel headed stud anchors and metal decks are cost-effective and widely used solutions for non-residential multi-story buildings, due in part to their enhanced strength and stiffness relative to non-composite systems. Because these systems use steel headed stud anchors welded onto steel flanges and encased in cast-in-place concrete slabs to achieve composite action, it is not possible to readily deconstruct and reuse the steel beams and concrete slabs. As the building industry is moving towards sustainability, there are clear needs for developing sustainable steel-concrete composite floor systems to facilitate material reuse, minimize consumption of raw materials, and reduce end-of-life building waste. This paper presents the behavior and design strategies for a sustainable steel-concrete composite floor system. In this system, deconstructable clamping connectors are utilized to attach precast concrete planks to steel beams to achieve composite action. The load-slip behavior of the clamping connectors was studied in pushout tests, and the test results showed that the clamping connectors possess similar shear strength to 19 mm diameter shear studs and much greater slip capacity. Four full-scale beam tests were performed to investigate the flexural behavior of the deconstructable composite beams under gravity loading and validate the connector behavior attained from the pushout tests. All the beams behaved in a ductile manner. The flexural strengths of the composite beam specimens closely match the strengths predicted for composite beams by the design provisions of the American Institute of Steel Construction (AISC).

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