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The realistic determination of damage estimation and building performance depends on target displacements in performance-based earthquake engineering. In this study, target displacements were obtained by performing pushover analysis for a sample reinforced-concrete building model, taking into account 60 different peak ground accelerations for each of the five different stories. Three different target displacements were obtained for damage estimation, such as damage limitation (DL), significant damage (SD), and near collapse (NC), obtained for each peak ground acceleration for five different numbers of stories, respectively. It aims to develop an artificial neural network (ANN)-based sustainable model to predict target displacements under different seismic risks for mid-rise regular reinforced-concrete buildings, which make up a large part of the existing building stock, using all the data obtained. For this purpose, a hybrid structure was established with the particle swarm optimization algorithm (PSO), and the network structure’s hyper parameters were optimized. Three different hybrid models were created in order to predict the target displacements most successfully. It was found that the ANN established with particles with the best position revealed by the hybrid models produced successful results in the calculation of the performance score. The created hybrid models produced 99% successful results in DL estimation, 99% in SD estimation, and 99% in NC estimation in determining target displacements in mid-rise regular reinforced-concrete buildings. The hybrid model also revealed which parameters should be used in ANN for estimating target displacements under different seismic risks.

While high-rise mass-timber construction is booming worldwide as a more sustainable alternative to mainstream cement and steel, in South America, there are still many gaps to overcome regarding sourcing, design, and environmental performance. The aim of this study was to assess the carbon emission footprint of using mass-timber products to build a mid-rise low-energy residential building in central Chile (CCL). The design presented at a solar decathlon contest in Santiago was assessed through lifecycle analysis (LCA) and compared to an equivalent mainstream concrete building. Greenhouse gas emissions, expressed as global warming potential (GWP), from cradle-to-usage over a 50-year life span, were lower for the timber design, with 131 kg CO2 eq/m2 of floor area (compared to 353 kg CO2 eq/m2) and a biogenic carbon storage of 447 tons of CO2 eq/m2 based on sustainable forestry practices. From cradle-to-construction, the embodied emissions of the mass-timber building were 42% lower (101 kg CO2 eq/m2) than those of the equivalent concrete building (167 kg CO2 eq/m2). The embodied energy of the mass-timber building was 37% higher than that of its equivalent concrete building and its envelope design helped reduce space-conditioning emissions by as much as 83%, from 187 kg CO2 eq/m2 as estimated for the equivalent concrete building to 31 kg CO2 eq/m2 50-yr. Overall, provided that further efforts are made to address residual energy end-uses and end-of-life waste management options, the use of mass-timber products offers a promising potential in CCL for delivering zero carbon residential multistory buildings.

As in many other building types, space efficiency in mid-rise timber apartment buildings is one of the critical design parameters to make a project feasible. Space efficiency depends on varying selection criteria related to construction materials, construction methods, and proper planning. To date, no study provides a comprehensive understanding of space efficiency in mid-rise timber apartment buildings. This paper examined data from 55 Finnish mid-rise timber apartment buildings built between 2018 and 2022 under the Finnish Land Use and Building Act to increase the understanding of which factors and design parameters influence the space efficiency of mid-rise timber apartment buildings. The main findings of this study indicated that: (1) among the case studies, the space efficiency ranged from 77.8% to 87.9%, and the average was 83%; (2) the mean values of the ratios of structural wall area to gross floor area, vertical circulation area to gross floor area, and technical spaces (including shafts) to gross floor area were found to be 12.9%, 2.6%, and 1.5%, respectively; (3) construction methods or shear wall materials make no significant difference in terms of space efficiency, and there is no scientific correlation between the number of stories and space efficiency; (4) the best average space efficiency was achieved with central core type, followed by peripheral core arrangement. This research will contribute to design guidelines for clients, developers, architects, and other construction professionals of mid-rise timber apartment building projects.

Numerous countries across the globe have witnessed the recent decades’ trend of multi-storey timber buildings on the rise, owing to advances in engineering sciences and timber construction technologies. Despite the growth and numerous advantages of timber construction, the global scale of multi-storey timber construction is still relatively low compared to reinforced concrete and steel construction. One of the reasons for a lower share of high-rise timber buildings lies in the complexity of their design, where the architectural design, the selection of a suitable structural system, and the energy efficiency concept strongly depend on the specific features of the location, particularly climate conditions, wind exposure, and seismic hazard. The aforementioned shows the need for a comprehensive study on existing multi-storey timber buildings, which correspond to the boundary conditions in a certain environment, to determine the suitability of such a construction in view of its adjustment to local contexts. Apart from exposing the problems and advantages of such construction, the current paper provides a brief overview of high-rise timber buildings in Europe. Moreover, it addresses the complexity of the design approach to multi-storey timber buildings in general. The second part of the paper highlights the importance of synthesising the architectural, energy, and structural solutions through a detailed analysis of three selected case studies. The findings of the paper provide an expanded view of knowledge of the design of tall timber buildings, which can significantly contribute to a greater and better exploitation of the potential of timber construction in Europe and elsewhere.

This paper investigates the correlation between ground motion parameters and displacement demands of mid-rise RC frame buildings on soft soils considering the soil-structure interaction. The mid-rise RC buildings are represented by using 5, 8, 10, 13, and 15-storey frame building models with no structural irregularity. A total of 105 3D nonlinear time history analyses were carried out for 21 acceleration records and 5 different building models. The roof drift ratio (RDR) obtained as inelastic displacement demands at roof level normalized by the building height is used for demand measure, while 20 ground motion parameters were used as intensity measure. The outcomes show velocity related parameters such as Housner Intensity (HI), Root Mean Square of Velocity (Vrms), Velocity Spectrum Intensity (VSI) and Peak Ground Velocity (PGV), which reflect inelastic displacement demands of mid-rise buildings as a damage indicator on soft soil deposit reasonably well. HI is the leading parameter with the strongest correlation. However, acceleration and displacement related parameters exhibit poor correlation. This study proposed new combined multiple ground motion parameter equations to reflect the damage potential better than a single ground motion parameter. The use of combined multiple parameters can be effective in determining seismic damages by improving the scatter by at least 24% compared to the use of a single parameter.

Soil-Structure Interaction (SSI) represents an interdisciplinary issue characterized by complex material and geometrical nonlinearities affecting mutually the supporting soil and the superstructure of the system during a seismic event that can compromise serviceability. In this study the following objectives are developed: i) to evaluate the effects of the inelastic supporting soil behavior on the interaction of soil-structure systems; ii) to investigate the changes in the dynamic behavior of archetype low and mid-rise moment resisting building frames when inelastic soil deformation develops. To reach these goals, numerical models of linear-elastic and nonlinear-inelastic underlain soil of buildings on shallow foundations are subjected to earthquake time histories with different frequency content. By employing the finite difference software FLAC2D, the direct method which is capable to tackle SSI issues is used to accounting for soil nonlinearities. A succession of parametric analyses is performed. The slenderness of the superstructure as well as the frequency content of input excitations are important parameters. Nonlinear analyses show a significant increase in deformability and damping of the soil-structure system, implying a consequent reduction of the seismic forces on the structure. As a result, the base shear values dropped by approximately 57.56%, 44.46%, and 69% in the 3, 6, and 9-story frames, respectively.

Seismic performance of existing buildings constructed before modern seismic design codes is one of the important problems of earthquake prone countries. Increasing life and economic losses after strong earthquakes shows the necessity of seismic performance assessment studies and methods. Therefore, in this study assessment methods recommended by different seismic codes were investigated and probabilistically assessed by comparing the fragility curves of existing low- to mid-rise RC structures. Building performances were determined according to TEC-2007, TBEC-2018, EC8/3 and ASCE 41-17. Eight different occupied buildings, classified according to construction dates (old and new) and story numbers (3 to 6), were selected and investigated by using these codes. At first, building capacity curves and damage limits, defined by the different code methods, were determined via pushover analyses. Structures were then subjected to more than 300 real strong ground motion (GM) records employing nonlinear dynamic analysis and fragility curves were obtained. Static analysis results showed that strength, stiffness and deformation capacity of new buildings are significantly higher than old ones according to all seismic codes considered and it is observed that TBEC-2018 gives the most conservative capacity estimations with respect to others. Comparison of fragility curves indicated that damage probabilities of TBEC-2018 and EC8/3 are higher than other seismic codes and this situation is valid for all story number and building age classes. In most cases TBEC-2018 and TEC-2007 results represent the upper and lower bounds of damage probabilities. It was also found that building age is the most effective parameter that affect the fragilities of existing buildings. Distribution of fragility curves imply that different code methods can give significantly different damage estimations under identical seismic demand levels.

The building and construction industry is one of the largest greenhouse gas producers, accounting for 39% of global emissions, most of these coming from concrete and steel. Mass timber construction (MTC) potentially offers a sustainable alternative to these traditional building materials. However, more research is needed to establish the sustainability credentials of MTC relative to traditional concrete and steel structures, especially for mid-rise structures. The aim of this study is to evaluate the environmental and cost performance of mid-rise mass timber buildings by conducting a life cycle assessment (LCA). The LCA uses a cradle-to-cradle approach, considering the global warming potential (GWP), freshwater use (FW), and total use of non-renewable primary energy resources (PENRT). Results indicated that mid-rise mass timber buildings have significantly lower impacts than concrete buildings, with their GWP approximately 30 times lower, FW about 20 times lower, and PENRT reaching a negative value. Additionally, the cost analysis revealed that MTC buildings can be cheaper to build and thus possibly more profitable than concrete buildings. These findings establish mass timber as a viable and sustainable option for the future of Australia’s construction industry.

A tropical Chennai city, is already enduring heat stresses in its urban areas and is extremely vulnerable to temperature rise. Furthermore, Chennai continues to expand, thus the need to conduct research and make informed decisions on sensible strategies and regulations on how to construct and with what to construct attains much significance in recent times. One of the major contributors to the urban heat is the materials used on the surfaces of the urban form. The current paper assesses and demonstrates the performance of two wall materials – Clay Brick and AAC, usually utilized in urban developments within the context of an optimal urban morphological region. This is accomplished by making a compact mid-rise urban form of residential typology and utilizing ENVI-met 4.0 and re-creating the outdoor microclimatic conditions with AAC and Clay Brick walls. The urban form created with the Clay brick walls are found to be cooler by 0.010°C. Compared to daytime, at night time, the outside air temperature with clay brick walls and AAC dividers are cooler respectively. This investigation additionally discovered that a huge distinction to outside air temperature for studied urban form structure can be made by expanding the Sky View Factor (SVF), contrasted with an adjustment of material. The understandings from this study can be expanded and be applied productively to impact changes in Urban development guidelines.

To develop the cold-formed steel (CFS) building from low-rise to mid-rise, this paper proposes a new type of CFS composite shear wall building system. The continuous placed CFS concrete-filled tube (CFRST) column is used as the end stud, and the CFS-ALC wall casing concrete composite floor is used as the floor system. In order to predict the seismic behavior of this new structural system, a simplified analytical model is proposed in this paper, which includes the following. (1) A build-up section with “new material” is used to model the CFS tube and infilled concrete of CFRST columns; the section parameters are determined by the equivalent stiffness principle, and the “new material” is modeled by an elastic-perfect plastic model. (2) Two crossed nonlinear springs with hysteretic parameters are used to model a composite CFS shear wall; the Pinching04 material is used to input the hysteretic parameters for these springs, and two crossed rigid trusses are used to model the CFS beams. (3) A linear spring is used to model the uplift behavior of a hold-down connection, and the contribution of these connections for CFRST columns are considered and individually modeled. (4) The rigid diaphragm is used to model the composite floor system, and it is demonstrated by example analyses. Finally, a shaking table test is conducted on a five-story 1:2-scaled CFS composite shear wall building to valid the simplified model. The results are as follows. The errors on peak drift of the first story, the energy dissipation of the first story, the peak drift of the roof story, and the energy dissipation of the whole structure’s displacement time–history curves between the test and simplified models are about 10%, and the largest one of these errors is 20.8%. Both the time–history drift curves and cumulative energy curves obtained from the simplified model accurately track the deformation and energy dissipation processes of the test model. Such comparisons demonstrate the accuracy and applicability of the simplified model, and the proposed simplified model would provide the basis for the theoretical analysis and seismic design of CFS composite shear wall systems.