scholarly journals Shrinkage-Induced Response of Composite Steel–Concrete Slabs: A State-of-the-Art Review

2021 ◽  
Vol 12 (1) ◽  
pp. 223
Author(s):  
Md Mahfuzur Rahman ◽  
Gianluca Ranzi

Composite steel–concrete slab is a floor typology widely used for building applications. Their design is usually governed by serviceability limit state requirements associated with the time-dependent response of the concrete. In this context, this paper presents a state-of-the-art review of research carried out to date on the long-term behavior of composite steel–concrete slabs. The particularity of this time-dependent response relies on the fact that the concrete cannot dry from the underside of the slab due to the presence of the profiled sheeting while it can dry from its upper surface. In the first part of the paper, a review of the work carried out on the identification of the time-dependent response of the concrete is presented by considering the peculiarities that occur due to the non-symmetric drying condition related to composite slabs. Particular attention is given to shrinkage effects and to the occurrence and influence of the non-uniform shrinkage gradient that develops in this form of construction over time. This is followed by the description and discussion of the experimental work performed on both simply-supported and continuous static configurations of composite slabs. In particular, the work published to date is summarized while highlighting the key parameters of the test samples and of the testing protocols adopted in the experiments. In the last part of the paper, available theoretical and design models proposed for the predictions of the shrinkage-induced behavior of composite slabs are presented and discussed.

2021 ◽  
pp. 41-59
Author(s):  
Gianluca Ranzi ◽  
Raymond Ian Gilbert

<p>This chapter presents a state-of-the-art review of work published to date on the time-dependent response of composite steel-concrete slabs. The key components of this form of construction are introduced in the first part of the chapter, followed by a review of the time-dependent behaviour of the concrete and how it affects the in-service response of composite slabs. Throughout the chapter, particular attention is given to recent experimental and modelling work related to concrete time effects, and how these affect the in-service response of composite slabs, including the development of non-uniform shrinkage gradients that have been recently shown to occur in composite floors due to the inability of the concrete to dry from its underside because of the presence of the profiled steel sheeting.</p>


2019 ◽  
Vol 275 ◽  
pp. 01001
Author(s):  
Xin Ye ◽  
Bo Shan ◽  
Qian Yue ◽  
Zhenyu Wang

Glubam-concrete composite (BCC) structure is a construction technique where glue-laminated bamboo beam is connected to an upper concrete slab using different types of connectors. The long-term behavior and creep mechanism of BCC system are very complex due to different time-dependent behavior of three components. This paper performed a series long-term push-out tests on four types of connections under static load. The tests lasted for a period of seven months in uncontrolled sheltered indoor condition. Important results such as the relative slip-time curves are presented in order to characterize time-dependent behavior of connectors. Furthermore creep coefficient constitutive models are provided for predicting the long-term behavior of connections.


2020 ◽  
Vol 34 (06) ◽  
pp. 10352-10360
Author(s):  
Jing Bi ◽  
Vikas Dhiman ◽  
Tianyou Xiao ◽  
Chenliang Xu

Learning from Demonstrations (LfD) via Behavior Cloning (BC) works well on multiple complex tasks. However, a limitation of the typical LfD approach is that it requires expert demonstrations for all scenarios, including those in which the algorithm is already well-trained. The recently proposed Learning from Interventions (LfI) overcomes this limitation by using an expert overseer. The expert overseer only intervenes when it suspects that an unsafe action is about to be taken. Although LfI significantly improves over LfD, the state-of-the-art LfI fails to account for delay caused by the expert's reaction time and only learns short-term behavior. We address these limitations by 1) interpolating the expert's interventions back in time, and 2) by splitting the policy into two hierarchical levels, one that generates sub-goals for the future and another that generates actions to reach those desired sub-goals. This sub-goal prediction forces the algorithm to learn long-term behavior while also being robust to the expert's reaction time. Our experiments show that LfI using sub-goals in a hierarchical policy framework trains faster and achieves better asymptotic performance than typical LfD.


2021 ◽  
pp. 137-156
Author(s):  
Alejandro Pérez Caldentey ◽  
John Hewitt ◽  
John van Rooyen ◽  
Graziano Leoni ◽  
Gianluca Ranzi ◽  
...  

<p>This chapter presents a number of case studies that deal with the service design of composite steel-concrete buildings associated with the time-dependent behaviour of the concrete. The particular focus of this chapter is to outline key design aspects that need to be accounted for in design and that are influenced by concrete time effects. The first case study provides an overview of the design considerations related to the time-dependent column shortening in typical multi-storey buildings by considering the layout of the Intesa Sanpaolo Headquarters in Turin as reference. The second case study focuses on a composite floor of a commercial building constructed in Australia and it provides an overview of the conceptual design used to select the steel beam framing arrangement to support the composite floor system while accounting for concrete cracking and time effects. The third case study deals with the Quay Quarter Tower that has been designed for the repurposing of an existing 50-year old building in Australia while accounting for the time-dependent interaction between the existing and the new concrete components of the building.</p>


2007 ◽  
Vol 13 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Algirdas Kudzys ◽  
Romualdas Kliukas ◽  
Antanas Kudzys

An effect of structural and technological features on the design methodology of hyperstatic precast reinforced concrete and composite steel‐concrete structures is discussed. Permanent and variable service, snow and wind loads of buildings and their extreme values are analysed. Two loading cases of precast reinforced concrete and composite steel‐concrete continuous and sway frame beams as propped and unpropped members are considered. A redistribution of bending moments for the ultimate limit state of beams is investigated. A limit state verification of hyperstatic beams by the partial factor and probability‐based methods is presented. It is recommended to calculate a long‐term survival probability of beams by the analytical method of transformed conditional probabilities.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Shiyong Jiang ◽  
Weilai Yao ◽  
Jin Chen ◽  
Tao Cai

External bonding of FRP laminates to the tension soffit of concrete members has become a popular method for flexural strengthening. However, the long-term field performance of FRP-strengthened RC members under service conditions is still a concern, and more work needs to be done. Based on concrete smeared-crack approach, this paper presents a finite-element (FE) model for predicting long-term behavior of FRP-strengthened RC beam, which considers the time-dependent properties of all components including the aging effect of concrete. According to the comparison between theoretical predictions and test results, the validity of the FE model is verified. The interfacial edge stresses in adhesive layer were determined through appropriate mesh refinement near the plate end, and their time-dependent characteristics were investigated. The results show that creep of concrete and epoxy resin cause significant variations of the edge stresses with time. According to the research in this paper, the FE approach is found to be able to properly simulate the long-term behavior of the FRP-strengthened beam and help us better understand the complex changes in the stress state occurring over time.


2020 ◽  
Vol 212 ◽  
pp. 110464 ◽  
Author(s):  
Huan Zhang ◽  
Yue Geng ◽  
Yu-Yin Wang ◽  
Qinghe Wang

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