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This paper aims to describe and demonstrate a quantitative areal openness model (AOM) for measuring the openness of floor plans. Creation of the model was motivated by the widely reported but rarely quantified link between openness and adaptability.

The model calculates values for three indicators: openness score (OS), weighted OS (WOS) and openness potential (OP). OS measures the absence of obstructions (walls, chases, columns) that separate areas in a floor plan. WOS measures the number of obstructions while also accounting for the difficulty of removing them. OP measures the potential of a floor plan to become more open. Indicators were calculated for three demolished case study buildings and for three adapted buildings. The case study buildings were selected because openness – or lack thereof – contributed to the owners' decisions to demolish or adapt.

Openness indicators were consistent with the real-world outcomes (adaptation or demolition) of the case study buildings. This encouraging result suggests that the proposed model is a reasonable approach for comparing the openness of floor plans and evaluating them for possible adaptation or demolition.

The AOM is presented as a tool for facility managers to evaluate inventories of existing buildings, designers to compare alternative plan layouts and researchers to measure openness of case studies. It is intended to be sufficiently complex as to produce meaningful results, relatively simple to apply and readily modifiable to suit different situations. The model is the first to calculate floor plan openness within the context of adaptability.

Punching can trigger catastrophic failures in flat slabs because of its sudden nature resulting from exceeding the shear capacity of slabs. Effect of using recycled aggregate, as an environmental-friendly alternative to traditional RC structures, on punching behavior of these slabs was not sufficiently investigated in the literature. Hence, this paper aims to experimentally study the effect of using recycled coarse aggregate (RCA) on the punching shear capacity (PSC) of RC flat slabs. The RCA is produced by crushing of waste of concrete standard cubes obtained from compression tests.

A total of 12 slab-column connection specimens with different slab thicknesses (140, 160 and 200 mm) and different RCA percentages (0%, 30% and 70%) were prepared and tested under a central point load, to test its effect on the behavior of flat slabs. The punching failure loads of the tested specimens were compared with those obtained according to the provisions of different international building codes.

Compared with natural aggregate concrete, mixes with 30% and 70% RCA experienced reductions in the compressive that did not exceed 4% and 21%, while reductions of 4% and 13% were observed for the tensile strength, respectively. The increase in the amount of RCA reduced the PSC by 0%–7%, 0%–4% and 4%–10% for slabs with a thickness of 140, 160 and 200 mm, respectively. For slabs with punching shear reinforcement (PSR), ACI 318 provided the closest estimation for the PSC by 9%, whereas EURO 2 overestimated the PSC by 25% and ECP 203 underestimated the PSC by 41%.

The provided conclusions are obtained from the conducted experimental work where a constant W/C ratio, aggregate type and a maximum aggregate size of 19 mm for the RCA were adopted.

Enhancement in the behavior of flat slabs with various thicknesses and amounts of RCA because of introducing PSR is experimentally evaluated. The failure loads of the tested slabs with recycled and normal coarse aggregates were compared against different code provisions.

I argue that the official story about the collapses of the Twin Towers and building 7 of the World Trade Center, according to which the collapses were caused by fire – combined, in the case of the Twin Towers, with the effects of the airplane impacts – cannot be true, for two major reasons. One reason is that fire has never, except allegedly three times on 9/11, caused the total collapse of steel-frame high-rise buildings. All (other) such collapses have been produced by the use of explosives in the procedure known as “controlled demolition.” The other major problem is that the collapses of all three buildings had at least 11 features that would be expected if, and only if, explosives had been used.

I also show the importance of the recently released of 9/11 Oral Histories recorded by the New York Fire Department. With regard to the Twin Towers, many of the firefighters and medical workers said they observed multiple explosions and other phenomena indicative of controlled demolition. With regard to building 7, many testimonies point to widespread foreknowledge that the building was going to collapse, and some of the testimonies contradict the official story that this anticipation of the building's collapse was based on objective indications. These testimonies further strengthen the already virtually conclusive case that all three buildings were brought down by explosives.

I conclude by calling on the New York Times, which got the 9/11 Oral Histories released, now to complete the task of revealing the truth about 9/11.

This study aims at introducing a claim management model based on building information modeling (BIM) for claims that can be visualized in BIM models.

Based on the results of a questionnaire survey, 10 claims were identified as claims that can be visualized in BIM models (named hard claims in this study). Then, a BIM-based claim management model was developed and used in a case study.

A BIM-based claim management model is represented. The claim management process through this model consists of four steps: (1) extracting project information, identifying conditions prone to claim and storing them into a relational database, (2) automatically connecting the database to building information model, (3) simulation of the claims in building information model and (4) final calculations and report.

The proposed model can provide benefits to parties involved in a claim, such as early identification of potential claims, large space for data storage, facilitated claim management processes, information consistency and improved collaboration.

There are a few studies on providing solutions to claim management based on BIM process. Hence, the original contribution of this paper is the attempt to set a link between BIM and claim management processes.

The main goal is to investigate the effect of size and location of opening and column size on the punching shear strength. Openings are often needed in order to install mechanical and electrical services. This process takes away part of the concrete volume which is responsible for resisting the shear forces and any unbalanced moment. Furthermore, the application of rectangular columns in flat slabs is commonly used in practice as they provide lateral stiffness to the building. They are also utilised in garages and multi-storey buildings where these elongated cross-sectional columns reduce the effective span length between adjacent columns.

This research is a numerical-based investigation that is calibrated based on a thirteen previously tested and numerically calibrated slab specimens with no openings. A parametric study is conducted in this study to consider the effect of other parameters, which are the size and location of opening and the rectangularity ratio of column in order to evaluate their effect on the punching shear capacity. A total of 156 models are developed to study these factors. Additionally, the predicted shear carrying capacity of the simulated slabs is calculated using the ACI318–19 and Eurocode (EC2-04) equation.

The presence of openings reduced the punching shear capacity. The small opening's location and orientation have almost no effect except for one slab. For slabs of large openings, the presence of openings reduced the punching capacity. The punching capacity is higher when the openings are farther from the column. The numerically obtained results of slabs with rectangular columns show lower punching capacity compared to slabs of squared columns with the same length of the punching shear control perimeter. The punching capacity for all slabs is predicted by ACI318–19 and Eurocode (EC2-04) and it is found that Eurocode (EC2-04) provided a closer estimation.

The slabs considered for calibration were reinforced with four different punching shear reinforcement configurations, namely; ordinary closed rectangular stirrups, rectangular spiral stirrups, advanced rectangular spiral stirrups and circular spiral. Generally, there has been limited research on concrete flat slabs with openings in comparison with other subjects related to structural engineering (Guan, 2009) and no research on punching shear with openings of slabs reinforced with these reinforcement schemes. The available research focussed on the effects of openings on the flexural behaviour of reinforced concrete slabs includes Casadei et al. (2003), Banu et al. (2012) and Elsayed et al. (2009). In addition, experimental tests that examined slabs supported on rectangular columns are very limited.

This paper examines the level of detail and complexity that one needs to incorporate in a computational finite element (FE) model to predict the thermal and structural response of steel high-rise building frames to fire. Comparisons are made between these models in terms of accuracy and efficiency. Performance related to three parameters was examined: (1) the representation of the structural system as a 3-D full frame model versus a 2-D plane-frame model, both of which include the steel frame and the floor slab; (2) the representation of the slab in the 2-D plane frame model; and (3) the effects of modeling the temperature profile of each steel member cross-section as non-uniform (i.e. allowing a thermal gradient to develop) versus uniform. Results indicate that the 2-D plane frame model can be reasonably used in some cases to predict the performance of the perimeter column and floor beams framing into them in a fire-exposed high-rise moment-resisting frame (MRF) with a significant savings in analysis run time. The slab has little influence on the structural analysis of a 2-D plane frame; however, the slab influences the thermal profile through the depth of the beams, and these temperature changes will produce a non-negligible change when calculating the behavior of the frame and should be accounted for. Results also indicate that models whose members have uniform temperature can be used to obtain reasonable estimates of the interaction between connected beams and columns. However, thermal gradients produce significant changes in the deflection mechanics and plastic P-M limit state behavior exhibited by non-uniformly heated beam-columns that experience a severe decrease in capacity; therefore, it is recommended that thermal gradients be included in models that are used to predict deflections or plastic limit state behavior.

This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column.

The focus is on a steel moment frame that uses welded-unreinforced flange-bolted web connections between the beams and columns. A three-dimensional finite element (FE) model was created in ABAQUS with temperature-dependent properties for steel based on the Eurocode. The model was validated against experimental data at ambient and elevated temperature.

The failure mechanisms in the FE model were consistent with experimental observations. Two scenarios were considered: fixed load with increasing temperature (i.e. simulating column failure prior to fire) and fixed temperature with increasing load (i.e. simulating column failure during fire).

A macro element (or component-based) model was also introduced and validated against the FE model and the experimental data, offering the possibility of analyzing large-scale structural systems with reasonable accuracy and improved computational efficiency.

This paper aims to develop a framework to assess the reliability of structures subject to a fire following an earthquake (FFE) event. The proposed framework is implemented in one seamless programming environment and is used to analyze an example nine-story steel moment-resisting frame (MRF) under an FFE. The framework includes uncertainties in load and material properties at elevated temperatures and evaluates the MRF performance based on various limit states.

Specifically, this work models the uncertainties in fire load density, yield strength and modulus of elasticity of steel. The location of fire compartment is also varied to investigate the effect of story level (lower vs higher) and bay location (interior vs exterior) of the fire on the post-earthquake performance of the frame. The frame is modeled in OpenSees to perform non-linear dynamic, thermal and reliability analyses of the structure.

Results show that interior bays are more susceptible than exterior bays to connection failure because of the development of larger tension forces during the cooling phase of the fire. Also, upper floors in general are more probable to reach specified damage states than lower floors because of the smaller beam sizes. Overall, results suggest that modern MRFs with a design that is governed by inter-story drifts have enough residual strength after an earthquake so that a subsequent fire typically does not lead to results significantly different compared to those of an event where the fire occurs without previous seismic damage. However, the seismic damage could lead to larger fire spread, increased danger to the building as a whole and larger associated economic losses.

Although the paper focuses on FFE, the proposed framework is general and can be extended to other multi-hazard scenarios.

This study aims to investigate the behavior of different types of stone columns, including the short and floating columns, as well as the ordinary and the geosynthetic encased stone columns (OSC and GESC). The effectiveness of the geosynthetic encasement and the impact of the installation using the lateral expansion method on the column performance is evaluated through a three-dimensional (3D) unit cell numerical analysis.

A full 3D numerical analysis is carried out using the explicit finite element code PLAXIS 3D to examine the installation influence on settlement reduction (ß), lateral displacement (U_x) and vertical displacement (U_z) relative to different values of lateral expansion of the column (0% to 15%).

The findings demonstrate the superior performance of GESC, particularly short columns outperforming floating counterparts. This enhanced performance is attributed to the combined effects of geosynthetic encasement and increased lateral expansion. Notably, these strategies contribute significantly to decreasing lateral displacement (U_x) at the column’s edge and reducing vertical displacement (U_z) under the rigid footing.

In contrast to previous studies that examined the installation effect of OSC contexts, this paper presents a comprehensive investigation into the effect of geosynthetic encasement and the installation effects using the lateral expansion method in very soft soil, using 3D numerical simulation. The study emphasizes the significance of the consideration of geosynthetic encasement and lateral expansion of the column during the design process to enhance column performance.

The purpose of this paper is to present the construction process innovations that enabled the successful delivery of the hybrid mass timber high-rise building in Canada, the Brock Commons Tallwood House at the University of British Columbia. It is one of a set of papers examining the project, including companion papers that describe innovations in the mass timber design process and the impact of these innovations on construction performance. The focus of this paper is on innovation in the construction phase and its relationship to innovations implemented in previous project phases.

A mixed-method, longitudinal case study approach was used in this research project to investigate and document the Tallwood House project over a three-year period. Both quantitative and qualitative data collection and analysis techniques were used. Members of the research team observed prefabrication and construction, conducted periodic interviews and reviewed project artefacts.

The research identified three innovation “clusters,” including the use of innovative tools, techniques and strategies in the design and construction processes and the role they played in delivering the project. The “clusters” were further characterized according to the type of “connectivity” they afforded, either facilitation, operationalization or materialization. These two perspectives support a compounding view on innovation and help to understand how it can flow throughout a project’s life cycle and across its supply chain. Three process-based innovations were initiated during the design phase, integrated design process, building information modeling and virtual design and construction and flowed through to the construction phase. These were seen to enable the creation of connections that were crucial to the overall success of the project. These innovations were operationalized and enacted through the construction phase as design for manufacturing and assembly and prefabrication, staged construction and just-in-time delivery, integration of safety and risk management and a rigorous quality control and quality assurance process. Finally, a full-scale mock-up was produced for practice and constructability assessment, materializing the radical product innovation that was the mass timber structure. These strategies are used together for a synergistic and integrated approach to increase productivity, expedite the construction schedule and develop an innovative building product.

This paper details an in-depth investigation into the diffusion dynamics of multiple systemic innovations for the construction process of a unique building project, the tools and techniques used by the construction manager and team, and the challenges, solutions and lessons learned.