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The purpose of this paper is to examine the relationship between building floor and labor productivity of the structural work including formwork installation and rebar fabrication/installation.

The case study methodology and learning curve theory are adopted for the paper. Records from the structural work of a 20-storey apartment building were analyzed to calculate floor-based labor productivities.

Labor productivity of the formwork activity increased more than twice in the first five floors. If the first cycle (floor 2) is omitted, the straight-line learning curve model shows a learning rate of 83.5 percent. Labor productivity of the rebar activity tended to increase in the first 15 floors. If the first two cycles are omitted, the straight-line learning curve model indicates a learning rate of 83.6 percent.

Future research is needed to examine and quantify factors that affect the level of learning in high-rise building construction. The relationship between building floor and labor productivity should be further investigated for other construction activities.

Practitioners should consider the relationship between building floor and labor productivity and learning effects when planning manpower and construction duration for individual activities and for a building.

The paper substantiates the hypothesis that labor productivity does not reach 100 percent of the normal level at the very first floors while they do not support the hypothesis that labor productivity does not reach 100 percent at the top floors.

This paper aims to investigate the operational mechanism, project performance, motives behind, benefits, difficulties and success factors of adopting the guaranteed maximum price (GMP) scheme based on a real‐life case study of Chater House, an international Grade A private office project in Hong Kong.

The case project was analysed by means of the related project documentation and a series of face‐to‐face interviews with the relevant senior project representatives.

All the interviewed key project stakeholders perceived that the GMP contract helped achieve competitive price, value for money and superior quality of products as well as provided stronger incentives to innovation and cost saving. The case study revealed that the overall success of this GMP project was underpinned by several key attributes.

The paper provides solid groundwork for client bodies and contracting organisations to develop a best practice framework for implementing successful GMP schemes in future construction.

Hybrid concrete construction is a technologically advanced approach to frame construction. It utilizes an optimal mix of structural materials;eg, in situ concrete with precast concrete and steelwork. The process of selecting an hybrid‐optimized solution, however, often requires several factors to be considered, eg, “hard”criteria such as time and cost, and “soft” criteria such as safety and aesthetics (to be considered simultaneously) – the complexities of which can often be a core barrier to implementation. This paper introduces the concept of hybrid concrete construction and presents a virtual prototyping tool to assist the decision‐making process. This model is able to import computer aided design information into a central database – the details of which are then layered with additional information; eg, hard and soft performance criteria and so on. Solutions can be interrogated and demonstrated through an interactive virtual environment, in which multi‐option scenarios can be evaluated against specific user‐defined criteria. Findings have identified several core benefits, including the ability to: justify decisions corroborated with detailed data; evaluate options against each other; interrogate objects at a much greater detail than before; and see the effects of changes in a “real‐time” environment.

In recent years, there has been an increased focus on creating sustainable buildings that have a reduced carbon footprint. The primary method to achieve this has been through reducing operational carbon of buildings. However, as the industry aims to produce “carbon neutral” buildings with extremely low operational carbon through measures such as insulation, embodied carbon (EC) component could get increased. As such, it is equally important to understand the state of EC emissions in buildings. The aim of this research was to analyse typical EC and cost profiles of school buildings within Australia to understand which building elements need more attention.

The research involved measuring EC of five classroom blocks in schools in Sydney through a case study research approach and document survey. Bills of quantities from these projects were analysed to estimate the EC and cost profiles of the buildings.

Results indicated that some elements such as roof, site works, upper floors and substructure had a higher cost also demonstrating an increased EC indicating a possibility of a relationship between carbon and cost. Accordingly, these elements were identified as the typical carbon hotspots within school buildings in Australia, which need greater attention in reducing EC.

The study explores the carbon–cost profile of Australian school buildings and highlights the importance of reducing EC in carbon hotspots.

During service period, the bridge structures will be affected by the environment and load, so the carrying capacity will decline. The purpose of this paper is to research on the bearing capacity of bridge structures with time.

Destructive test and non-linear finite element analysis are carried out by utilizing two pretensioning prestressed concrete hollow slabs in service for 20 years; using the structural test deflection value to simulate the stiffness degradation of the service bridge and the finite element calculation results verify the accuracy of the calculation.

The flexural rigidity of the main beam when the test beam is destructed is degraded to approximately 20 percent of that before the test, which agrees well with the result of finite element analysis and indicates that the method of deducing the flexural rigidity of the structure according to the measured deflection value can effectively simulate the rigidity degradation law of the bridge in service. The crack resistance property of the test beam degrades obviously and the ultimate bearing capacity of the bending resistance does not degrade obviously.

The research results truly reflect the destruction process, destructive form, bearing capacity and rigidity degradation law of the old beam of the concrete bridge in service for 20 years and can provide technical basis for optimization design of newly built bridges of the same type and maintenance and reinforcement design of existing old bridges.

The concept of buildability is an approach to architectural design which relates to the awareness of the designer for the method of construction of the building. It is the taking into consideration of the process of construction to a high degree in the construction of the building. The opposite of this approach could be loosely called an ‘artistic’ method, where the designer hands a concept drawing to somebody else and says ‘build that’, with little concern for how the design should be built (definition contributed by James Harrison, Senior Lecturer, Department of Architecture, National University of Singapore). In addition to this design orientation, buildability, as viewed by the building industry, is the ease with which the building can be built. Yet these definitions seem to lack precision when placed into operation in the design environment. To understand the notion of buildability further, a study of concrete construction techniques, pre‐cast or in situ, were used to evaluate the extent to which buildability techniques were employed by the designers and the effectiveness of the approaches. The methodology used followed existing approaches to studying buildability but expanded and focused on two case study buildings. In this way, a more holistic picture of the influence of the construction system and its buildability could be gained.

This suspension bridge, with its main span of 3,300 ft., is expected to be opened in 1963. It will be the largest in Europe and the fourth largest in the world. A number of interesting improved techniques will be used in protecting it from corrosion and, in particular, the post‐tensioning cables which anchor the side towers to the base rock are expected to last over a century.

The partially prestressed concrete beam with unbonded tendon is still an active field of research because of the difficulty in analyzing and understanding its behavior. The finite-element (FE) simulation of such beams using numerical software is very scarce in the literature and therefore this study is taken to demonstrate the modeling aspects of unbonded partially prestressed concrete (UPPSC) beams. This study aims to present the three-dimensional (3-D) nonlinear FE simulations of UPPSC beams subjected to monotonic static loadings using the numerical analysis package ANSYS.

The sensitivity study is carried out with three different mesh densities to obtain the optimum elements that reflect on the load–deflection behavior of numerical models, and the model with optimum element density is used further to model all the UPPSC beams in this study. Three half-symmetry FE model is constructed in ANSYS parametric design language domain with proper boundary conditions at the symmetry plane and support to achieve the same response as that of the full-scale experimental beam available in the literature. The linear and nonlinear material behavior of prestressing tendon and conventional steel reinforcements, concrete and anchorage and loading plates are modeled using link180, solid65 and solid185 elements, respectively. The Newton–Raphson iteration method is used to solve the nonlinear solution of the FE models.

The evolution of concrete cracking at critical loadings, yielding of nonprestressed steel reinforcements, stress increment in the prestressing tendon, stresses in concrete elements and the complete load–deflection behavior of the UPPSC beams are well predicted by the proposed FE model. The maximum discrepancy of ultimate moments and deflections of the validated FE models exhibit 13% and −5%, respectively, in comparison with the experimental results.

The FE analysis of UPPSC beams is done using ANSYS software, which is a versatile tool in contrast to the experimental testing to study the stress increments in the unbonded tendons and assess the complete nonlinear response of partially prestressed concrete beams. The validated numerical model and the techniques presented in this study can be readily used to explore the parametric analysis of UPPSC beams.

The developed model is capable of predicting the strength and nonlinear behavior of UPPSC beams with reasonable accuracy. The load–deflection plot captured by the FE model is corroborated with the experimental data existing in the literature and the FE results exhibit good agreement against the experimentally tested beams, which expresses the practicability of using FE analysis for the nonlinear response of UPPSC beams using ANSYS software.

The purpose of this paper is to present the results of experimental testing of steel rebars at elevated temperatures. Three types of bars available in the local market in Pakistan were used. These data are not available in Pakistan.

Three types of bars were used, which included cold-twisted ribbed (CTR), hot-rolled deformed (HRD) and thermo-mechanically treated (TMT) bars. The diameter of the bar of each type was 16 mm. The bars were heated in an electrical furnace at temperatures which were varied from 100°C to 900°C in increment of 100°C. Bars of each type were also tested at ambient temperature as control specimens. The change of strength, strain and modulus of elasticity of the bars at high temperatures were determined.

The mechanical properties of the bars were nearly unaffected by the temperatures up to 200°C. CTR bars did not show yield plateau and strain hardening both at ambient and high temperatures. The high temperature yield strength and elastic modulus for all the three types of bars were similar at all temperatures. The yield plateau of both the HRD and TMT bars disappeared at temperatures greater than 300°C. The ultimate strength at high temperature of the HRD and TMT bars was also similar. The behaviours of the HRD and TMT bars changed to brittle beyond 400°C as compared to their behaviours at ambient temperature. The CTR bars exhibited ductile characteristics at failure at all the exposure temperatures relative to their behaviour at ambient temperature.

The parameters of the paper included the rebar type and heating temperature and the effects of temperature on strength and stiffness properties of the steel bars.

Building fire incidents have increased in Pakistan. As reinforced concrete (RC) buildings exist in the country in significant numbers, the data related to elevated temperature properties of steel is required. These data are not available in Pakistan presently. The presented paper aims at providing this information for the design engineers to enable them to assess and increase fire resistance of RC structural members.

The presented paper is unique in its nature in that there is no published contribution to date, to the best of authors’ knowledge, which has been carried out to assess the temperature-dependent mechanical properties of steel reinforcing bars available in Pakistan.

This research study focuses on investigating the seismic performance of non-straight beams in steel structures and exploring the mechanism by which plastic hinges are formed within these beams. The findings contribute to the understanding of their behaviour under seismic loads and offer insights into their potential for enhancing the lateral resistance of the structure. The abstract of the study highlights the significance of corners in structural plans, where non-coaxial columns, diagonal elements or beams deviating from a straight path are commonly observed. Typically, these non-straight beams are connected to the columns using pinned connections, despite their unknown seismic behaviour. Recognizing the importance of generating plastic hinges in special moment resisting frames and the lack of previous research on the involvement of these non-straight beams, this study aims to address this knowledge gap.

This study examines the seismic behaviour and plastic hinge formation of non-straight beams in steel structures. Non-straight beams are beams that connect non-coaxial columns and diagonal elements, or deviate from a linear path. They are usually pinned to the columns, and their seismic contribution is unknown. A critical case with a 12-m non-straight beam is analysed using Abaqus software. Different models are created with varying cross-section shapes and connection types between the non-straight beams. The models are subjected to lateral monotonic and cyclic loads in one direction. The results show that non-straight beams increase the lateral stiffness, strength and energy dissipation of the models compared to disconnected beams that act as two cantilevers.

The analysis results reveal several key findings. The inclusion of non-straight beams in the models leads to increased lateral stiffness, strength and energy dissipation compared to the scenario where the beams are disconnected and act as two cantilever beams. Plastic hinges are formed at both ends of the non-straight beam when a 3% drift is reached, contributing to energy damping and introducing plasticity into the structure. These results strongly suggest that non-straight beams play a significant role in enhancing the lateral resistance of the system. Based on the seismic analysis results, this study recommends the utilization of non-straight beams in special moment frames due to the formation of plastic hinges within these beams and their effective participation in resisting lateral seismic loads. This research fills a critical gap in understanding the behaviour of non-straight beams and provides valuable insights for structural engineers involved in the design and analysis of steel structures.

The authors believe that this research will greatly contribute to the knowledge and understanding of the seismic performance of non-straight beams in steel structures.