Composite Floor Slabs Research Articles

Flexural performance of innovative thin-walled steel–timber composite floor slabs

A floor slab carries and distributes the floor load in a structure and is an important component that affects overall structural performance. Therefore, it is important to investigate the mechanical properties of such materials. In this study, flexural performance tests under static load are conducted for an innovative thin-walled steel–timber composite floor slab, and the failure mode, bearing capacity, stiffness, deflection, and strain development are investigated. The results show that the floor slab can be quickly assembled using self-tapping and wood screws and exhibits good flexural performance. Using ABAQUS finite-element software, the effects of the oriented-strand board (OSB) thickness, thin-walled–steel-plate height, steel strength, and boundary conditions on the flexural performance of composite floor slabs are investigated. Furthermore, based on the EN1995–1-1 code and equal-section conversion principle, the simplified beam-unit model is established for the theoretical calculation of the composite floor slab. The effective bending stiffness is calculated by considering the influence of the slip modulus of the connector, and the stress distribution law of the section is analysed. The results provide a reliable design basis and reference for the application of thin-walled steel–timber composite floor slabs in engineering practice.

Composite floor slab effect on seismic performance of steel-framed-tube structures with shear links

High-strength steel-framed-tube structures with low-yield-point shear links (SFT-RLYPSL) exhibit exceptional lateral and torsional stiffness, coupled with significant energy dissipation capacities. This study aims to investigate teh influence of composite floor slabs on the seismic performance of these structures. Expanding on previous research concerning SFT-RLYPSL, this paper presents a simplified numerical model for the SFT-RLYPSL, incorporating the influence of the composite floor slab. The developed model employs the steel4 constitutive relation to accurately depict the behavior of low-yield-point steel. Furthermore, the simplified numerical model utilizes two-node link elements to simulate shear links and integrates composite beams to represent the influence of the composite floor slab. Using this simplified model, elastic-plastic pushover analysis is performed on five distinct SFT-RLYPSL structural cases, and nonlinear time-history analysis is conducted on three structural configurations. The investigation explores various aspects of the seismic performance of SFT-RLYPSL, including modal behavior, pushover curves, progression of overturning failure, time-history roof displacements, inter-story drift angles, base reactions, inter-story shear, failure modes, residual inter-story drift angles, and the manifestation of shear lag phenomena. The findings suggest that incorporating the composite floor slab effect enhances initial stiffness and peak load capacity in pushover analysis, leading to distinct three-stage pushover curves. During nonlinear time-history analysis, the composite floor slab effect increases structural stiffness, decreases roof displacements and inter-story drift angles, while simultaneously increasing base reactions, worsening component damage, and raising collapse risk. Nevertheless, its influence on residual inter-story drift angles remains relatively minor, with a mitigating effect on the shear lag phenomenon. Importantly, the degree of this impact varies with alterations in floor slab thickness and seismic intensity, highlighting the critical importance of considering the composite floor slab effect in structural design deliberations.

Pseudo-Dynamic Tests on Frame–Shear Wall Structure with Precast Concrete Diaphragm

In order to study how to improve the spatial action of precast monolithic composite floor slabs, and examine replacing the cast-in-place surface layer for reducing the weight of structure, we used pseudo-dynamic tests on one-quarter scale models of two-span and three-story frame structures. The lateral load tests compared the stresses and displacements with a cast-in-place floor frame–shear wall structure (SJ1) and a precast monolithic floor frame–shear wall structure with X horizontal braces at the bottom of the floor (SJ2). The results show the X horizontal braces can improve the spatial action. Structural integrity (SJ2) as well as the effective transmission of the horizontal force can be ensured by additional X bracing at the bottom of the rigidity of the floor without a cast-in-place concrete topping. The results show that X horizontal braces more effectively transfer horizontal stress, which provides a beneficial reference for similar research.

Study on the Tensile and Shear Performances of Fully Precast Partially Composite Floor Slab Joints

This study explored the tensile and shear characteristics of fully prefabricated partially composite floor slab joints through the design and testing of two tensile specimens, three steel–concrete specimens, and three concrete–concrete shear specimens. These tests aimed to evaluate how various connection designs influence the joints’ load-bearing capabilities and failure patterns. The findings revealed that the tensile specimens predominantly showed bond failures at the interface of the precast and cast-in-place layers, accompanied by rebar pull-out. Incorporating reinforcing bars or sleeves was found to potentially increase their ultimate load-bearing capacity by about 20%. The shear failures in the steel–concrete specimens were primarily due to interactions between the steel beam and adjacent composite slab, whereas the concrete–concrete specimens mostly underwent local crushing at the load application point and failure at the bonding interface. These observations affirmed the accuracy of the existing methods for calculating tensile and shear strengths, offering vital insights for the architectural design and construction of such floor joints.

Design Analysis of Sustainable Composite Slab using Profiled Steel Sheeting: A Case Study based on BS 5950-4: 1994 and EN 1994-1-1: 2004

Composite slabs, combining the structural benefits of steel and concrete, are an integral part of modern construction due to their high load-bearing capabilities and efficiency. Steel sheeting provides tensile reinforcement, while the concrete offers compressive strength, contributing to the sustainability and durability of the flooring systems. Recent projects in Malaysia, such as the construction of high-rise Merdeka 118 and PNB Mall have demonstrated the effectiveness of composite slabs in achieving efficient, robust, and environmentally friendly structures. This study basically involves in examining and reassessing the composition of floor slabs using profiled steel from NS BlueScope Lysaght. Technically, this study has amended a manual excel spreadsheet to reassess the design and in-depth analysis of the composite concrete slab using a case study from PNB Mall projects. Through the checking and re-evaluation process, several comments and critical discussions have been made, categorized into two subjects: (a) discussions on the formwork/construction stage analysis, and (b) evaluations on the composite (slab) stage analysis. In conclusion, the MegaFloor modelling software is capable of designing and analyzing composite floor slabs when comparing it to the amended excel spreadsheet calculations. The manual design calculations adhere to BS 5950 Part 4, as well as EN 1994-1-1:2004.

Analyzing the Environmental, Economic, and Social Sustainability of Prefabricated Components: Modeling and Case Study

The building industry has significant environmental, economic, and social impacts. The trend of construction industrialization to promote sustainable development is becoming increasingly evident. As an essential component of this process, prefabricated components provide a foundation for studying the sustainability of prefabricated buildings. This study proposes a life cycle sustainability assessment (LCSA) model involving environmental, economic, and social aspects to assess the sustainability of prefabricated components. The sustainability impacts on the raw material extraction and production, off-plant transport, material processing and component manufacturing, on-plant transport, and component storage stages are comprehensively assessed. The LCSA model is applied to four types of prefabricated components: interior wallboards, precast stairs, composite beams, and composite floor slabs. The results show that the precast stairs exhibit the highest sustainability score and that the performances of environmental, economic, and social pillars of four components are slightly different. These findings enhance our understanding of the sustainability of prefabricated components and broaden the scope of LCSA applications. The established sustainability assessment model is expected to help guide prefabrication scheme designs and production plan optimization, further encouraging the wider adoption of sustainable practices in construction.

Retracted: Impact Sound Insulation Performance Testing of Nano-Inorganic Composite Floor Slabs for Green Buildings.

[This retracts the article DOI: 10.1155/2022/5642361.].

Resilient performance of steel connections with low yield point fuses considering the effect of RC floor slab

The beam-column connection of a steel frame equipped with replaceable low yield point steel cover plates (SF-LYCP) was proposed to address the significant repair challenge and financial losses caused by beam-column connection brittle failure after an earthquake. According to an experimental study, the SF-LYCP exhibited outstanding bearing capacity, ductility, energy dissipation, and post-earthquake rapid recovery performance. To explore the effect of the reinforced concrete (RC) floor slab on the mechanical behavior of SF-LYCP in a natural working environment, the finite element method of steel beam-column connection with low yield point (LYP) steel cover plates considering the effect of the RC floor slab (SF-LYCP-RCslab) was developed and analyzed by ABAQUS. The results demonstrated that the proposed finite method was able to accurately predict the behavior of SF-LYCP-RCslab. The load capacity, initial stiffness, and energy dissipation capacity of the SF-LYCP-RCslab were increased in comparison to the SF-LYCP. The LYP cover plates in the SF-LYCP-RCslab still played the desirable role of structural fuses. However, the concrete of the RC floor slab had severe damage and prevented the quick replacement of repairable LYP cover plates. Based on these findings, four improved strategies for the SF-LYCP-RCslab were proposed to reduce concrete damage and increase the replacement convenience of damaged elements. Comprehensively considering the bearing capacity, ductility, energy dissipation, structural fuse function, concrete damage, and post-earthquake rapid recovery performance, the improved strategy, which adopted a profiled steel–concrete composite floor slab with a gap, was recommended in steel frame beam-column connection design.

Mechanical properties of energy sustainable round bamboo - Phosphogypsum composite floor slabs

Round bamboo is a natural building material with excellent mechanical properties and has broad application prospects in green buildings. To realize the protection of round bamboo and promote the resource utilization of phosphogypsum, a kind of round bamboo-phosphogypsum composite (BPC) floor slab is proposed in this paper. To study the flexural performance of the round bamboo-phosphogypsum composite floor slabs, considering the factors of the thickness of the phosphogypsum, the number of dovetail nails, the number of round bamboo poles and the span, the flexural tests of 11 floor slabs were carried out, the influence of the factors on the flexural performance of the floor slabs was analyzed, and the calculation methods of the flexural stiffness and bearing capacity of the floor slabs were established. The results show that the bearing capacity, ductility coefficient and flexural stiffness of the control specimen are increased by 31.26%, 51.19% and 3.39 times compared with the bamboo skeleton. The ductility and flexural stiffness of the floor slab decrease with increasing span. The bearing capacity of floor slab increases with the increasing bamboo number and decreasing span. The calculation methods of flexural performance of the floor slabs established in this paper have certain accuracy. The round bamboo-phosphogypsum composite (BPC) floor slab realizes the efficient utilization of resources, which has reference significance for green buildings and sustainable development.

Experimental Study on Flexural Behavior of the Composite Bottom Slab of the Stiffened Steel Truss

In order to study the influence of rib size on the flexural performance of the new reinforced truss concrete composite floor slab, two precast reinforced concrete floor slabs and one ordinary reinforced truss composite floor slab were designed and manufactured for flexural performance tests. The failure mode of the concrete slab under uniform load was analyzed, and the influence of rib size on the flexural capacity of the floor slab was studied. The results show that the stiffening of the steel truss composite slab can significantly improve the stiffness of the precast slab and effectively solve the problem of excessive deflection of the precast slab during construction. On the basis of the experimental study, the influence of the top chord steel bar diameter, concrete rib height and rib width on the short-term stiffness of the floor is deeply analyzed by using the finite element refined modeling. The results show that the diameter of the top chord reinforcement and the width of the concrete rib are positively related to the stiffness of the composite slab, and the height of the concrete rib has little effect on the initial stiffness of the precast slab, which mainly plays a role in the later stage.

Innovative composite floors for sustainable schools

This article describes a project to investigate the dynamic behaviour of a prefabricated timber-concrete composite floor slab developed for the Department for Education's GenZero sustainable schools programme. The GenZero initiative involves a new building system made of a kit of parts that could be manufactured off site and then assembled on site to create diferent confgurations of secondary school. The slab is constructed of a precast concrete deck on glulam ribs, with two interlayers. The project investigated the effect of both the interlayers and different shear connectors on the performance of the slab.

Deepening Design Technology of Super High-rise steel Structure

In view of the difficulties in deepening design of super-high-rise steel structures, we try to use Tekla Structures 3D intelligent steel structure simulation design software to carry out the corresponding deepening design, and verify the implementation effect of the deepening design with engineering practice, providing reference and reference for similar projects. The research shows that Tekla Structures is a very efficient and convenient software for steel structure deepening design; The connection nodes between giant columns and trusses should be divided in sections according to the principle of dividing along the section and along the column height, and reasonable lifting lug plates and studs for site use should be set; For hot-rolled steel plate composite floor slab, full-length reinforcing plates with the same thickness as the steel plate shall be set longitudinally on both sides of the splice weld of the adjacent unit steel plate; The thick plate welding shall be subject to process review in advance.

Experimental and theoretical analysis on truss construction robot: Automatic grasping and hoisting of concrete composite floor slab

AbstractThe development of various construction robots can significantly reduce the construction labor intensity and risk. We present an experimental task of a truss construction robot, including automatic grasping and hoist positioning of concrete composite floor slab. And, a control strategy matching the construction robot is proposed to solve the following problems: (a) Due to the widespread manufacturing errors of building components, the position deviation of diagonal web reinforcement on concrete composite floor slab may cause grasping failure. (b) The chaotic surface of the floor slab seriously affects the recognition accuracy of the grasping target. (c) The large mass and inertia of heavy‐duty hanger and concrete composite floor slab make it difficult for robot to achieve accurate positioning under eccentric load condition. The machine vision recognition system ensures that if the diagonal web reinforcement is detected more than half of the grasping path, the grapple hook can change the grasping path independently to prevent it from colliding with the offset diagonal web reinforcement. An anticollision and grasping path planning method based on machine vision is proposed to improve the success rate and efficiency of automatic grasping. The mean value of proportional speed and proportional position is introduced as the evaluation speed and evaluation position of driving wheel to improve the accuracy of multiwheel synchronization. Moreover, we analyzed the robot performance from actual grasping and hoist positioning process of the concrete composite floor slab. The experimental results show that the robot has a good performance on the automatic grasping and hoisting of the concrete composite floor slab.

Effect of interior gravity framing system and composite floor slab action on the lifetime seismic risk assessment of steel frame buildings subjected to mainshock–aftershock sequence

The structural analysis practices of steel moment-resisting frame buildings often neglect the participation of the interior gravity frames and composite floor slab action in their lateral strength and stiffness. In addition, the effects of aftershocks are frequently omitted in steel frame buildings’ seismic performance evaluations. This study investigates the effects of structural modeling assumptions and the incorporation of aftershocks on the seismic vulnerability and time-dependent lifetime seismic risk for a group of steel moment-resisting frame buildings. Three ductile steel moment-resisting frame buildings of four, eight, and twelve stories are examined in this study. The results indicate that the seismic performance of steel special moment-resisting frame buildings is substantially underestimated when based on structural models that ignore additional sources of lateral stiffness and strength owing to the interior gravity frame system and the composite floor slab action. In addition, when ignoring aftershocks from the seismic performance assessment, the possibility of catastrophic failure could be underestimated by a factor of 11 at the end of an assumed 50-year lifetime for the steel frame buildings, underscoring the need to account for aftershock effects in evaluating the collapse safety of the selected buildings.

Flexural Performance of Prestressed Composite Recycled Aggregate Slabs with Steel Tube Trusses

A new type of prestressed composite recycled aggregate floor slab was developed and its flexural performance was studied. The composite floor comprises a top cast-in-place slab made of recycled coarse aggregate concrete and a bottom precast concrete slab with grouted steel tube trusses. The cracking load, ultimate load, deflection, steel tube strain, concrete strain and failure process are studied for different contents of recycled coarse aggregates. Results show that the mechanical performance of the prestressed composite recycled aggregate slab has two distinctive stages. And the load bearing capacity decreases with the increase in the amount of recycled coarse aggregates. When the composite slab fails, the prestressed steel wires in the tension zone yield and concrete in the compression zone is crushed. This failure characteristic reflects that the reinforcement ratio of the component is appropriate. The cracking moment and ultimate moment calculation formulas of the composite slab are established and could predict the cracking and failure points. In the formulas, the influence of the amount of recycled coarse aggregates on the flexural capacity is considered. By controlling the content of recycled aggregates, the composite slabs with steel tube trusses can be sued in practical applications.

Impact Sound Insulation Performance Testing of Nano-Inorganic Composite Floor Slabs for Green Buildings.

To explore the detection of impact sound insulation performance of nano-inorganic composite floor slabs for green buildings, for 4 types of floor slab practices in a certain area, we carry out the detection of the sound insulation performance of the floor impact sound and analyze and summarize the test results. Finally, several common technical measures to effectively improve the sound insulation performance of floor impact sound are summarized. Experimental results show that with floor slabs using nano-inorganic composite material FBP, the impact sound insulation performance of the floor slab can be greatly improved. FRP materials have the advantages of high strength, lightweight, and good corrosion resistance. They are more and more widely used in construction engineering. At this stage, for environmental friendly green building materials and nano-inorganic composite materials with certain effects, their main practice and application play an important role. It is proved that adding FBP material can greatly improve the impact sound insulation performance of floor slabs.

Shaking table test of fabricated concrete shear wall structure and study on damage mechanism of strong earthquake

Prefabricated construction technology has the advantages of high quality, high efficiency, low cost, energy saving and environmental protection, and has developed rapidly in China in recent years. Based on the design and construction concept of “equivalent to cast-in-site”, the seismic effect and strong earthquake damage mechanism of the overall structure considering boundary constraints are studied. In order to promote the application and development of high-assembly-rate concrete shear wall structures in high-intensity areas, a reduced-scale structural model of sleeve connection was designed and fabricated based on the Chinese seismic code. Through the multi-level strength-increasing shaking table simulation test, the dynamic characteristics, earthquake response, failure process and strong earthquake disaster mechanism of the model structure are comprehensively analyzed. The research results show that the prefabricated concrete shear wall structure can achieve the predetermined seismic fortification purpose according to the specified construction requirements. Secondly, Under the stepwise excitations of PGA 0.035–0.40 g, the flexural and shear failure of the coupling beam are the main failure mode, and the damage of the coupling beam with a small span-height ratio (1.33) is more serious. Furthermore, Under the stepwise excitations of PGA 0.62–0.90 g, the seismic capacity of the model structure is greatly reduced and there is a risk of collapse. The failure modes of the structure after a strong earthquake include four types: bending-shear composite failure of composite beams, horizontal interface penetration between composite beams and floor slabs, horizontal interface penetration between prefabricated walls and floor slabs, and vertical cracking at the junction surface of prefabricated walls and cast-in-site restraint elements. The latter three are unique forms of fabricated concrete shear wall structures. Finally, according to the whole process data of the test, the bottom shear force and top displacement of the model structure are calculated, and the hysteresis curve, skeleton curve and equivalent lateral stiffness are established. It is hoped that this study can provide a reference for the seismic design of high-rise fabricated concrete shear wall structures.

Structural robustness evaluation of steel frame buildings with different composite slabs using reduced-order modeling strategies

This study presented reduced-order modeling methods for evaluating the structural robustness of steel frame buildings with different composite floor slabs under ground floor column loss scenarios. The adequacy of the reduced-order modeling technique was justified by relatively high-fidelity models, which were verified by a full-scale composite floor test and detailed material coupon tests. This reduced-order modeling method was applied to the progressive collapse simulation of a five-story prototype building. The effect of floor slabs, slab rebars, and steel decks' longitudinal continuity on its progressive collapse resistance was examined. Composite slabs with four different profiled steel decks were considered in this study, which are trapezoidal deck, dovetail deck, reentrant deck, and rebar-truss deck; in addition, reinforced concrete (RC) slab was also considered for comparative purposes. To account for the possible sudden column failure scenario in practice, an energy-based approach was used to convert the quasi-static response curves to dynamic response curves. The structural robustness was evaluated by comparing each column failure case's dynamic ultimate capacities with corresponding design requirements. The structural robustness of prototype buildings under progressive collapse scenarios was summarized and discussed. The analysis results showed that the structural robustness of the prototype building with rebar-truss composite slab was higher than that with RC slab or other composite slabs. The prototype building with floor slabs using HRB400 rebars had higher structural robustness than that using CRB550 rebars.

Electrochemical Preparation of Recycled Self-Compacting Concrete Composite Beams and Their Application in Prefabricated Buildings

In order to solve the problems of electrochemical preparation of recycled self-compacting concrete composite beams and their application in prefabricated buildings, we need to meet the requirements of national housing industrialization and green buildings, make up for the low development capacity of prefabricated buildings, and improve the speed of housing construction and the rapid development of the construction industry. Now the prefabricated building has entered a period of rapid growth. However, the research on the construction technology of the prefabricated building is still in its infancy, and there are many difficulties and challenges in the construction. The deformation and internal force of a prefabricated residential laminated floor slab in the construction process of prestressed PK slab transportation, stacking, hoisting, and the laminated cast-in-situ layer will affect the normal use of the building. However, at present, there is less mechanical analysis of its construction process, so there is blindness in the formulation, implementation, and inspection of the construction scheme. Through the social survey of 200 people, 179 people believe that prefabricated buildings will be better than traditional buildings. Therefore, by participating in the practice of prefabricated housing engineering, the key mechanical problems in the construction of the composite floor slab of prefabricated housing are explored and found.

Experimental investigation on flexural behavior of steel-concrete composite floor slabs with distributed fiber optic sensors

This research investigates the flexural behavior of steel-concrete composite floor slabs with distributed fiber optic sensors based on pulse pre-pump Brillouin optical time domain analysis. The distributed sensors were embedded in trapezoidal concrete slabs and provided in-situ real-time monitoring of initiation and evolution of cracks in the profiled slabs of four composite floor slabs. This paper proposes a sensor deployment method for real construction of civil engineering structures and evaluates the effects of headed studs and concrete casting on the flexural behavior of composite floor slabs and the performance of distributed sensors. The composite floor slabs failed with concrete cracks, accompanied by yielding in the steel beams and slippage between concrete and steel. The distributed sensors captured complex crack patterns of the concrete slabs in the evolution of the damages in the composite floor slabs. The strengths and limitations of distributed sensors are discussed to promote applications and further development.