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Earthquake-induced soil liquefaction can generate excessive damage to building structures due to significant reduction in soil effective stress. With increasing urbanisation and population growth, the performance of closely spaced buildings, such as those in towns and cities, is of greater concern where structure–soil–structure interaction (SSSI) may occur in conjunction with full or partial liquefaction. This study investigates the seismic performance of isolated and adjacent structures built on shallow foundations on soils of different permeability (i.e. with different amounts of drainage and therefore generating different amounts of excess pore water pressure) using a combination of dynamic centrifuge modelling and finite-element modelling. The results demonstrate that the reduction in free-field ground surface intensity measure (specifically, Housner intensity) due to increasing liquefaction can be correlated to an index which is the normalised integral of excess pore pressure ratio (ru) with depth. This index can express the amount of liquefaction uniquely, even when full liquefaction occurs to only partial depth, or where excess pore water pressures are increased but below the level of full liquefaction at all depths. This underlying correlation means that structural demand reduction (e.g. reduction in inter-storey drift ratio) with liquefaction (SSI effect) can be linked to either: (a) the ru–depth index; (b) the depth of the liquefaction front, which can be estimated from a liquefaction triggering analysis; or (c) the ground surface intensity amplification/attenuation in the free field from the results of one-dimensional free-field soil column analyses. Where there are adjacent structures, a strongly beneficial SSSI effect on co-seismic settlement and a detrimental effect on drift in non-liquefied soil, as observed in this and previous studies, reduced towards a null effect in both cases with increased liquefaction, with liquefaction appearing to isolate the structures from each other (at least for the configuration considered herein). This has also been linked to the amount of amplification/attenuation of surface ground motion in the free field (or amount of liquefaction) as a simple indicator of the likely importance of SSSI effects in liquefiable soil.

This article presents the results of a theoretical study of the infl uence the outside air infi ltration through the enclosing structures of the walls on the amount the air’s exchange in low-rise residential buildings. Based on the information analysis from offi cial documents of state statistical and analytical bodies, the most frequently used external wall structures in modern low-rise residential construction have been determined. Based on the provisions analysis of modern regulatory documents in the construction’s fi eld, the minimum values the required air exchange were determined and the calculations of the values the infi ltration air fl ow through the outer walls for various premises of low-rise residential buildings were made. Based on the results of the analysis and calculations was made a generalizing conclusion that for the considered premises of modern low-rise residential buildings, at the expense of the infi ltration of outside air through the enclosing structures of the walls, it is impossible to provide even 20 % of the minimum air exchange.

Application of base isolators undermines the drawback of earthquake to the structures. In recent decades, various base isolators have been applied, and several researchers have conducted research on the influence of base isolated structures. In this study, a rubber bearing with steel rings called RRB is designed and applied in 3 to 6- story steel and concrete structures, and the results are compared to fixed base and isolated base structures with lead rubber bearing (LRB). Isolators are first modeled in finite element software Abaqus, and hysteresis analysis is done, and effective stiffness and damping of each isolator is obtained. The average results for effective stiffness of the LRB is 110.88 (ton/m) and for the RRB is 82.48 (ton/m). The average damping for the LRB is 18.44%, and for the RRB is 47.02%. The analysis of structures is considered nonlinear time history and is done with the earthquake records of Kobe, Tabas and Manjil. The results of drift, acceleration and base shear are presented. The acceleration results of RRB isolated base structure show that 3, 4, 5 and 6-story buildings has a reduction by 42.16, 43.36, 51.83 and 57.16%. Moreover, the shear results of RRB isolated base structures comparing to the corresponding fixed base structure has had a reduction of 55.5, 47.16, 37.93 and 56.83 for 3, 4, 5 and 6-story structures. The results for drift indicate that utilization of the RRB leads to a decrease by 35.33, 50, 54.5% and 59.66 for 3, 4, 5 and 6-story structures, respectively.

Base isolation systems are efficient in decoupling the building from the ground during earthquakes, leading to a reduction in seismic demand to be experienced by the isolated building. Although Steel Reinforced Elastomeric Isolators (SREIs) have been proven to perform well under earthquakes, they are mostly applied to special buildings and are not a cost-effective solution for low-rise buildings in developing countries like India. Although there are existing studies on Unbonded Fibre Reinforced Elastomeric Isolator (UFREIs), effectiveness of alternative low-cost fibres was not studied. Hence, this paper focuses on parametric studies of UFREI systems with various locally available fibres. Initial dimensions of UFREI required for seismic isolation of a two storeyed framed building were approximated. For these specific dimensions, performance of UFREI numerical models with various low cost locally available fibres were studied and compared with high strength fibres by conducting parametric studies using ABAQUS. Interesting results obtained by varying the strength, thickness and number of fibre layers are discussed in detail. A new parameter, peak stress ratio ( S n ) was proposed which helps in deciding the type of fibre to be used in UFREI systems. Based on the observations from these studies, a suitable configuration of UFREI was proposed. Significant improvement in the seismic performance of the base isolated building was observed from the linear static and dynamic analyses.

This study evaluates the effects of infills on the seismic resilience of special steel moment resisting frames. For this purpose, three structures of 4, 8 and 12 story are selected and designed in three different modes namely without infills, with Infills and with infills having openings. Finite element models are developed in OpenSees software. Seismic capacity and demand of structures are calculated using incremental dynamic analysis (IDA). Then, using statistical methods and probabilistic functions based on inter story drifts of the structures, fragility curves are obtained according to the HAZUS instructions. Finally, by quantifying damages, changes in seismic resilience are assessed. This makes it possible to relate the probability functions, fragility and resilience curves in an integrated approach. The results of the analysis show that infills may significantly reduce structural damages and an increase its resilience at different risk levels. The role of infills in increasing the resilience index is highlighted by the increase in risk level. This increase has been far more significant in low rise frames. It is also observed that the decreasing effect of infill openings in resilience index of high-rise buildings is less than low-rise ones although insignificant in some cases which can be overlooked.

A full-scale steel portal frame structure, explicitly designed to utilize stressed skin action, was tested to destruction in the early 1970′s. At this time, it was not possible to perform any detailed analysis of such structures; however, using modern computational techniques, detailed Finite Element Models (FEMs) have now been developed. These FEMs show an excellent agreement with the reported test results, including following the nonlinear behaviour to complete collapse. The validated model was then extrapolated into a multi-bay portal structure of more realistic length, and the effect of cladding on the strength and flexibility of the frames was established under both vertical and horizonal loading. Under a distributed vertical load, the cladding initially had little influence although, once the internal frames reached a complete collapse mechanism, the cladding prevented structural collapse until the cladding also failed. However, under horizontal load, the coupling between frames was significant, particularly in the multi-bay case, leading to high forces in the cladding and the structure/cladding interface. The tested frame was stocky and low rise, typical of its time. Today, with taller, more flexible modern frames, stiffer and potentially less robust cladding systems will resist an even more significant proportion of the horizontal load; a warning to the construction industry that parasitic diaphragm action should not be ignored.

This July, All-Russian Housing Congress brought together about five thousand participants, including specialists inhousing construction, real estate business, mortgage lending, information technologies, interregional transactions,education and training in the real estate market. Among the most relevant topics, discussed by the researchersand practitioners, the following ones can be highlighted: at present, the market of standard private housingconstruction is not mature enough, construction is mainly performed by the citizens themselves; the mortgagemarket, focused on this segment, is in its infancy; there is a need to introduce a standard for the integrateddevelopment of territories in respect of low-rise suburban housing construction, as due to its absence banksand investors do not have clear guidelines for assessing the investment attractiveness of projects; innovativeapproaches in the field of low-rise construction, latest methods of digitalization of investment and constructionactivities at all stages and levels of the project life cycle; developing a reliable mortgage lending mechanism forthis market segment; adoption and implementation of up-to-date standards for the integrated development of lowriseconstruction areas. According to the co-authors, the above-listed topics encompass the main directions forthe development of this industry.

Reinforced concrete (RC) frame with masonry infills is a building typology where an RC frame is constructed first and subsequently masonry wall panels (infills) are constructed to enclose spaces within a building. Several low-rise RC frame buildings experienced shear failure in past earthquakes in India and Nepal due to inadequate size of RC frame members, poor reinforcement detailing, improper confinement of RC columns, and lack of quality workmanship. The objective of this paper is to establish a simplified criteria for predicting a failure mechanism in low-rise RC framed buildings with masonry infills. Three criteria were examined and a parametric study was performed on 36 numerical models to determine the parameters which affect the occurrence of flexural or shear failure mechanism in masonry-infilled RC frame structures. The study showed that the main factors influencing a failure mechanism are the ratio of shear capacities for RC columns corresponding to the shear and flexural failure mechanisms and the ratio of shear stiffnesses for RC columns and infilled frame. The results also showed that RC frames with a larger column longitudinal reinforcement ratio have higher chances for shear failure, given the same frame and infill dimensions and mechanical properties. The paper may be relevant for engineering professionals and researchers interested in assessing seismic safety of non-engineered low-rise RC frame buildings.

Design of reinforced concrete (RC) buildings with a direct-displacement-based design (DDBD) method has been used extensively for the last few decades around the world. As compared to force-based design (FBD) method, DDBD provides advantages in cost-reduction, construction timing, and better structural performance. This paper investigates the DDBD methodology for G + 3 storied RC buildings, having different structural configurations by varying bays in the longitudinal and transverse directions, but having the same total plan area. The selected case-study RC buildings are analysed via non-linear time history analysis considering seismicity of zone-V of Indian regions. A suite of different spectrum compatible ground motions is used. The seismic behaviour has been analysed in terms of base-shear ratio, ductility demand, displacement profiles and drift ratios. The results illustrate that the DDBD procedure proves to be useful in designing RC buildings situated in seismic regions of India and are competent enough to withstand lateral forces due to seismic excitations.

Рассматривается технология изготовления строительным 3D-принтером стен малоэтажных зданий с архитектурным декором. Каждую стену здания изготавливают в горизонтальном положении на площадке, покрытой антиадгезионным материалом. Вначале строят на площадке с помощью 3D-принтера несъемную опалубку из бетона по периметру стены. На площадке размещают оконные и дверные коробки, закладные элементы для монтажа электропроводки и других устройств. Укладывают нижний и верхний слои бетона с арматурными сетками, а промежуточный слой из пенобетона или иного материала с малой теплопроводностью. На поверхности уложенного бетона выполняют с помощью 3D-принтера рельефный архитектурный декор с использованием обычного или цветного бетона. При сборке малоэтажного здания готовые стены ставят в вертикальное положение и угловые стыки армируют. Для этого связывают сваркой вертикальные арматурные стержни с концами сеток. Далее закрывают стык стен угловой опалубкой и полость в угловом стыке заполняют бетоном. The article discusses the manufacturing technology for building the walls of low-rise buildings with architectural décor using 3D construction printer. Each wall of the building is made in a lying position on a site covered with anti-adhesive material. Initially, a permanent concrete formwork is built on site along the perimeter of the wall with a 3D printer. Then window and door frames, electrical, and plumbing embedded elements are positioned. Lay the lower and upper layers of concrete include a reinforcing mesh, and the intermediate layer is made of foam concrete or other material with lower thermal conductivity. The surface of the wall module can be covered with a décor printed using ordinary or colored concrete. When assembling a low-rise building, the finished walls are placed in a vertical position and the corner joints are reinforced. For this, vertical reinforcing bars are connected by welding to the ends of the meshes. Next, the wall joint is closed with corner formwork and the cavity in the corner joint is filled with concrete.

This paper presents a comprehensive assessment method of the fragility of low-rise cold-formed steel (CFS) framed wall structures subjected to wind hazards considering the fragility of both the main structure and the cladding system. The effects of wind directions on the fragility of CFS framed wall structures were also studied. For the main structure, the fragility curve is established using the maximum interstory drift ratio (ISDRmax) as the performance index for assessing the wind fragility of the structure. For the cladding system, the probabilistic models of the wind load and the cladding component resistance are established based on Monte Carlo simulation, and then methods for the fragility assessment of single cladding components and the cladding system under wind hazards considering the influence of the number and arrangement of the cladding components are proposed. The results indicated that, under strong wind, the cladding system may be damaged before the required wind resistance capacity of the main structure is exhausted. In particular, the roof sheathing is the most prone to damage, followed by the stud wall. That is, before the main structure is severely damaged or collapses, the cladding systems may be severely damaged, rendering the structure unusable. Therefore, the comprehensive assessment of the fragility of this type of structure subjected to wind hazard considering the fragility of both the main structure and the cladding system is more accurate. This study is of great significance for the improvement of the wind resistance performance of CFS structures and the popularization of this type of structure.

PurposeGiven the climatic context and economic challenge of Ghana in its developmental strides, energy use of office buildings continues to be a task on the economy. Therefore, the study was about finding measures that could reduce cooling loads in 10 office buildings. The paper presents the outcome of a long-term study of the thermal conditions in a selected number of office buildings in Accra and Kumasi, Ghana.Design/methodology/approachThrough long-term monitoring of environmental data, the buildings were consequently modelled in a simulation application. Thereafter, a validation of the simulation models (using regression coefficients, r2 of 0.53–0.90) was undertaken towards finding measures to reduce cooling loads.FindingsThe results showed various potentials of efficient lighting, thermal mass, night ventilation, insulation to attic floors, efficient glazing, blind deployments, etc. in reducing cooling loads in the range of 2–17.5%. By combining the potential measures to study their synergistic effects on the loads, 35, 39 and 38% improvements were achieved for the low-rise, multi-storey and fully glazed office buildings.Originality/valueThese potential measures ought to be incorporated in the design, specification, construction and operation of Ghanaian office buildings to reduce the burden on the economy and the environment. Now more than ever, there is the need for climatic regions to come up with empirical data that could help relieve the world's economies from the post-pandemic stress.

In this study, linear and non-linear static analysis of low-rise models representing two-bay two-story and three-bay three-story reinforced concrete framed structures designed as per Indian standard codes (IS 450:2000 and IS 1893:2016) for the high seismic region using Envelope loading combination are assessed with and without the Guidelines of U.S. (GSA) General Services Administration. The purpose of this study is to describe the applicability of Finite Element software in assessing the behavior of seismically designed low rise structure before and after losing vertical structural element column with and without considering dynamic increase factor, and the results indicate demand resistance ratios acquired from elastic linear analysis and the hinge formation pattern obtained from non-linear elastic analysis are similar for Envelope loading combination and GSA loading combination, thus the dynamic increase factor of 2 recommended by the U.S. General Services Administration guidelines for static analysis can be underestimated for low-rise reinforced concrete framed models designed seismically as far as progressive collapse resistance is considered, since both types of loading combinations (in which one combination considers only normal design load path method while the other combination considers alternate load path methods) acquire same type of results, thus confirms seismically designed low rise models does possess inherent property towards progressive collapse resistance. This study provides a good example and summary for the construction industry and can be used by design engineers while designing low-rise progressive collapse-resistant structures.

In the current work, a series of seismic analyses of asymmetrical small, low-rise 3-D reinforced concrete (R/C) buildings is executed along with the investigation of the effect of deformable soil on the seismic structural response. The time-history analyses are performed by using earthquake accelerograms in two horizontal and one vertical direction, while the elastoplastic behavior of R/C elements is regarded with a fiber mechanical analytical model. The foundation of the buildings is designed in two ways, either as R/C footings interconnected with R/C beams or as foundation mat. The Soil-Structure Interaction (SSI) effect on the seismic response is studied not only through the global structural characteristics but also through detailed parameters, such as the redistribution of the internal forces of R/C elements. The simple maximum softening damage index is employed to evaluate the elastoplastic behavior of R/C structures.

A number of aerodynamic devices to perturb or modify the flow over low-rise buildings are proposed. The purpose of these devices is to reduce the adverse effects of wind over low-rise buildings and to mitigate the pressures on the roofs to lower vacuum levels. Pressure measurements were performed on a scaled down model of the well-known TTU experimental building of the Wind Engineering Research Facility (WERFL) at TTU University. Different results were obtained: reduction of average peek vacuum, smoothing of windward pressure distribution on the roof and narrowing and localizing of the suction pressure zones on the roof. Results that may be of interest to other disciplines such as heat transfer are also reported.

Artificial light at night (ALAN) on tall or upward-pointed lighting installations affects the flight behavior of night-migrating birds. We hypothesized that common low-rise lights pointing downward also affect the movement of nocturnal migrants. We predicted that birds in flight will react close to low-rise lights, and be attracted and grounded near light sources, with a stronger effect on juveniles during their autumn migration. We conducted a controlled longitudinal experiment with light-emitting diode floodlights and considered nearby structures that turn on lights at night. We analyzed 1501 high-resolution 3D nocturnal flight paths of free-flying migrants and diurnally captured 758–2009 birds around experimental lights during spring and autumn 2016, and spring 2017. We identified change points along flight paths where birds turned horizontally or vertically, and we considered these indicative of reactions. Flight paths with and without reactions were generally closer to our experimental site in spring than in autumn when the lights were on. Reactions were up to 40% more likely to occur in autumn than in spring depending on the threshold magnitude of turning angle. Reactions in spring were up to ∼60% more likely to occur at ∼35 m from the lights than at >1.5 km. In autumn, some vertical reactions were ∼40% more likely to occur at ∼50 m from the lights than at >2.2 km. Interactions between distance to lights and visibility or cloud cover were consistent with known effects of ALAN on nocturnal migrants. Under poor visibility, reactions were up to 50% more likely to occur farthest from structures in spring, but up to 60% more likely to occur closest to lights in autumn. Thus, the effects of ALAN on night-migrating land birds are not limited to bright lights pointing upward or lights on tall structures in urban areas. Diurnal capture rates of birds were not different when lights were on or off for either season. To our knowledge, this is the first study to show that low-rise lights pointing downward affect night-migrating birds. Although the interpreted reactions constitute subtle modifications in the linearity of flight paths, we discuss future work that could verify whether the protection of nocturnal migrants with lights-out programs would have greater impact if implemented beyond urban areas and include management of low-rise lights.

Investigations were carried out to study the mechanical performance under uniaxial load of unplastered and plastered straw bales. Results from tests on 30 rice straw bales indicated nonlinear load-bearing properties with large deformations and anisotropy. Since the deformations observed did not conform to the current building code requirements, the evaluation of ultimate bearing capacity through the maximum axial vertical load was not possible. To obtain the design strength of rice straw bales in composite walls, further 21 specimens of plastered straw bales were also tested in compression. The permissible deformation of the straw bales was evaluated. It is noteworthy that the large deformability of straw bales can reduce the damage to structures after an earthquake. Consequently, the straw bale use can widely enhance the seismic performance of low-rise buildings.

In recent years, regarding buildings that serve as bases for disaster relief work and as living spaces, the social desire is for continued use of and less repair work for such buildings after earthquakes. To meet that kind of wish, post-quake building damage must be kept to the slightest minimum. With the aim of continues use of buildings after earthquakes, this report deals with medium and low-rise steel structure buildings, giving consideration to practical guidelines for base shear coefficients in order to minimize building damage to the slightest possible after foreshocks, main shocks and aftershocks. The first priority was to theoretically speculate based on energy balance to derive a calculation formula for cumulative plastic deformation ratio corresponding to level of damage, the speed conversion value equivalent to total energy input and the natural period parameterized base shear coefficient (α1). Also, the application of this calculation formula to foreshocks, main shocks and aftershocks was made possible by introducing a cumulative energy spectrum. The derivation processes for the above are explained in Chapters 2 and 3. Next, from analysis results of α1 applied to seismic waves widely used in actual design, consideration was given to base shear coefficients that meet the current seismic code together with guidelines for base shear coefficients that would make it possible for continued use of buildings after earthquakes. By setting base shear coefficient guidelines in which a building’s Ds value is 0.4 or more with the 1st natural period at less than 1s, or where the Ds value is 0.25 or more with a natural period of 1s to 2s, the degree of damage is less than moderate even for earthquakes that very rarely occur, which fulfills the required performance in the seismic code. If a design is oriented to continuous use of the building after foreshocks, main shocks and aftershocks, then the pragmatic assessment would be to aim for a natural period of 1s or more and a base shear coefficient of 0.45 or greater as the Ds value. These analytical considerations are explained in Chapter 4. Finally, Chapter 5 explores the observation waves for the Pacific Coast of Tohoku Earthquake (2011) and Kumamoto Earthquake (2016), considering base shear coefficients that will make continued use of buildings possible after earthquakes. Regarding a building with first natural period of less than 1s, a short period region (greatly exceeding the energy input of an earthquake that very rarely occurs [a wave arrival count of 2]) existed in the energy input of observation waves of accumulated foreshocks, main shocks and aftershocks. Thus, this research confirmed that a natural period of 1s or more and a Ds value of 0.45 or more as the base shear coefficient will, generally speaking, minimize damage to less than slight for the abovementioned accumulated observations waves.

The urban population in India is growing at a fast rate along with the growth in the construction of residential concrete houses. Though a majority of these residential buildings are still of natur...

A case study on the internal pressure induced by a local failure on the vulnerable gable roof of a low-rise building was extensively conducted experimentally and numerically. Five roof opening configurations were tested in the wind tunnel under three different boundary layer conditions, based on 1:40 scaled models. The effects of opening shape, opening position, opening ratio, building internal volume, and wind speed on peak transient and steady-state internal pressures were studied. The study results indicate that the peak transient and steady-state internal pressures and the corresponding transient overshoot ratio all increase with an increasing opening ratio. The peak steady-state internal pressure is little affected by the approaching wind speed; while the peak transient internal pressure coefficient shows a significant linear relationship with the wind speed. The coupling effect of vortex shedding and Helmholtz resonance in double building volume compensation situation may cause larger fluctuating internal pressure. Both the vortex shedding and Helmholtz resonance reduce the internal pressure coherence to some extent. The agreement between the numerical and experimental results is much better for the mean internal pressure than that for fluctuating internal pressure or peak internal pressure.

Peninsular Malaysia lies in a low seismic zone, but its building structures had come across the concrete deterioration due to the seismic ground motion originated from far or near field. Notably, most of the building structures in this country are designed based on wind load only. Moreover, current practice to analyze or design a building such as FEMA 368 and EC8 underestimated the effect of repeated excitations. These guidelines only considered single vibrations to evaluate the framed structure. Therefore, the objective of this study was to assess the performance of private educational institute reinforced concrete building with generic 3D two storey frame structure under multiple seismic motions. Structural model was examined under series of earthquake motions which include pre-shock, main shock and aftershock scenario. Total of 7 seismic ground motions were selected to quantify the structural frame model by nonlinear dynamic time history analyses. Pseudo-dynamic ground motions were recorded on shaking table ranging from 0.18 g to 0.82 g were applied onto the building model for assessment. The outcome of this study has identified that the low-rise building model survived at higher PGA values. Moderate damages (0.25 ≤ DI < 0.40) were recorded after passing through multiple ground motions. Moreover, low seismic vibrations with large ground movement had caused ground floor storey act as soft storey. The study concluded that low rise building model had higher tendency to absorb lower to higher ‘g’ values and resist the earthquake loading due to the strength of framed structure.

The initial fire-fighting facility design plan may need to be changed during the construction of fire-fighting facilities because of alterations in the architectural design or the flexibility of the site situation. The difference between the 'design drawings at the stage of consenting for building approval' (Original design drawings) and the 'design drawings at the stage of consenting for use approval' (Completion drawings) ultimately leads to changes in the construction cost and in the performance of the fire-fighting facility. Therefore, to secure the fire safety of buildings and prevent human casualties, relevant case analyses and consequent institutional and systematic supplementation are necessary. In this study, six recently completed buildings were selected as target sites, the application rate of each fire-fighting facility in the initial design was analysed, and the need for institutional supplementation was suggested. As a result, owing to the design change, the construction cost and net construction cost could be reduced by up to 19% compared to those based on the original design. In particular, In particular, the sprinkler facility was found to match only 78.7% of the original design drawing in the completion drawing, showing the largest rate of design change among fire-fighting facilities.

A resilience and seismic safety evaluation method of under-qualified concrete structures designed based on codes prior to the introduction of earthquake provisions is presented. A numerical method for evaluating and improving a structure’s performance and resilience through jacketing and Carbon Fiber Reinforced Polymers (CFRP) retrofitting was developed. The model analyzed the structure’s existing condition, inadequate elements were identified, and segments that required strengthening were determined. Retrofitting and external reinforcing techniques were applied, and their effectiveness evaluated. Elements identified as insufficient were subjected to a strengthening iteration process to ensure that all qualifications were fulfilled. It was proven that the numerical simulation was accurate, cost-effective and time-saving in evaluating deficient structures and the effectiveness of their strengthening methods. The numerical model and analysis in conjunction with the technology of jacketing and CFRP retrofitting provide a fast and straightforward solution for older structures in ameliorating their resilience and overall performance

Engineers may make various decisions based on the engineering judgment while they design a building, or may choose different methods for modeling the structural components, especially the way by which the deteriorating behavior of elements should be incorporated. Such decisions cause the engineering demand parameters (EDPs) to depend on the deterioration properties of a building considered in a seismic performance assessment. It is important to know how much those properties are going to be effective on or valuable for designing of low-rise asymmetric RC buildings, or how they affect the design decision makings. For the example buildings, the seismic performance is evaluated by performing the incremental dynamic analysis (IDA) and monitoring the lateral deformation versus the load-resisting capacities of the models. By introducing a new criterion, the influence of the deterioration properties on the seismic performance of models is then assessed, providing the results for both torsionally-stiff and torsionally-flexible models. Although the deterioration affects the torsionally-stiff models more rapidly than the torsionally-flexible types, its impacts depend on the value of hysteretic model parameters. In contrary to the torsionally-flexible models, the influence of deterioration on the torsionally-stiff buildings is sensitive to the building asymmetry. However, the variation of deterioration rate is very significant for the torsionally-flexible models. So, it is important to make careful design decisions for reducing the undesirable effects of the deterioration.

This paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.

PurposePrefabricated housing has become a boom industry across the world; however, the uptake of offsite construction (OSC) approaches in Australian low-rise buildings is rather low compared with high-rise buildings in other countries. This study aims to investigate and analyse the adoption of different levels of OSC approaches and the selection of different procurement options in Australian low-rise residential buildings.Design/methodology/approachThe research objectives were pursued through a mixed research method. An empirical questionnaire survey was carried out with 35 professionals in the Australian building and construction industry. Semi-structured interviews were conducted with 20 interviewees and analysed using thematic analysis method in NVivo software.FindingsThe research results found that the most suitable OSC level for Australian low-rise buildings is components-based prefabrication and identified the barriers to OSC uptake for each OSC level. The study also showed that the best option of procuring prefabricated products is from Australian manufacturers, followed by Australian suppliers/dealers and overseas manufacturers. Panelised prefabrication and components-based prefabrication are ranked as the most suitable OSC approaches for Australian manufacturers. Modular prefabrication is regarded as the most suitable for overseas manufacturer, while components-based prefabrication is the most suitable for Australian suppliers/dealers.Originality/valueThe selection of various OSC approaches and different procurement options in the low-rise residential buildings are scarcely explored topic, and thus, this study provides knowledge of interest for both researchers and practitioners.

Most of the existing low rise RCC buildings with 4 to 6 floors were constructed pursuant to the code provisions without detailed Earthquake analysis. To comply with the revised code provisions, it is essential to build up the seismic resistance of the existing buildings. International building safety agencies such as NEHRP, FEMA, and ATC etc., formulated the Performance-based design methods to verify the seismic resistance of the existing buildings and also recommend the retrofit the building to achieve the targeted performance. Pushover method (nonlinear static analysis) is one of the methods. This paper describes the increase of seismic capacity of structure with the additional steel contribution from 25 % to 75% increase in the beams near the beam-column joints. Moreover, this additional steel is placed up to 02.L, 0.25L and 0.3L of the beam span. To accomplish the above parameters, 4-storey, 5-storey and 6-storey rectangular framed structures are analyzed with the pushover analysis. The seismic capacity curves in terms of base shear versus displacement are illustrated. It is found that 10 to 25% of base shear is increased when beams are provided with additional reinforcement from 25% to 75% @0.2L. In this case of increasing the additional steel length from 0.20L to 0.3L, nearly 5% increase of the base shear is observed in width direction but no augmentation is observed in the length direction of the building.

In South Asian countries concrete is mostly used as construction material, especially for low rise structures. Still steel is not predominantly used in high rise structures. Besides, Reinforced Cement Concrete (RCC) and steel structures; composite structures can be built to get maximum benefit of the steel and concrete, as well to produce reliable and economic structures. In this paper comparative study of nine storey hospital RCC and steel building is carried out. For the modelling and analysis of RCC and steel structure ETABs software is used. Comparative study of different parameters like base shear, load carrying capacity, displacement, time period, axial force, and cost is carried out with RCC and steel structures. Final results illustrates that steel structures are more suitable for high rise structures, less time consuming and they are cost effective too.