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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.

The areas of low-rise buildings in Leningrad in the period from 1944 to 1950 are considered. The current state of development is reflected. A detailed analysis of the features of residential blocks is carried out on the example of the Udelnaya district. Graphic diagrams showing the location of low-rise blocks in the modern urban fabric are presented. The process of involving creative teams of architects in the design of low-rise buildings is described. The general characteristics of urban planning and architectural aspects of development are given. The characteristic features of the planning structure formed in each area of low-rise construction are analyzed. The assessment of the preservation of the building ensemble at the present stage is given. The existing urban fabric of the Udelnaya district is presented, indicating the gradual formation of development. The architectural features of low-rise buildings in the Udelnaya district are analyzed using the example of three types of houses. A comparative analysis of three types of houses is presented in tabular form. The comparative analysis provides a graphical representation of the main facades and the three-dimensional composition of buildings. The graphic scheme illustrates the silhouette of Yeletskaya street in the Udelnaya district. A general description of the area improvement environment is given. As a result of the study, the positive and negative sides of low-rise buildings are identified. In conclusion, the operational disadvantages of the analyzed low-rise buildings are indicated. Based on all the materials presented in the article, it is proposed to renovate low-rise areas as a single ensemble.

In this paper, it is proposed to carry out the sustainable design of steel building systems were explained briefly as per codal provisions. Light gauge steel is one of the technologies which have very high potential for low rise residential and commercial buildings. This eliminates the huge reduction in construction time. Finally a comparative study is achieved by designing a industrial steel warehouse using conventional steel as well as cold formed steel by using a design software ETABS.

This article investigates the basic provisions of design of earthquake-resistant low-rise buildings and formulated the basic principles of design of earthquake-resistant buildings by design, erected in seismic areas: frame, volume-block, large-panel, with walls of large blocks, with walls of monolithic concrete, with walls of complex structure, with load-bearing walls of brick or stone, wooden buildings with walls of local materials. Seismically unfavorable conditions, which are designed as a large part of the terrain land (steep shores, gorge, water, etc.), impact disturbance, physiographic processes, rocks, soils, spills, mine workings and destruction of tectonic sites disasters surrounding areas. The main buildings and other structures to strengthen and strengthen the foundation, how to use any additional measures.

Buildings with open ground stories are more vulnerable to soft story mechanisms, which might lead to building collapse in a moderate quake. To mitigate these negative effects, retrofitting...

The article identifies the features of the use of composite reinforcement in the pile and strip foundation of a two-story house. When designing the foundations, the complex geological conditions of the construction site were taken into account: a high level of groundwater, their aggressiveness with respect to metal reinforcement (seasonal fluctuation of water supply and water treatment at the time of engineering and geological surveys at a level of 2.8 m); the possibility of landslide processes on the slopes; insufficient knowledge and anisotropy of the properties of the bulk layer, significant thickness of the bulk layer, excluding its removal and replacement. An analytical calculation and a numerical experiment were carried out, the following features of the use of composite reinforcement were established: more effective in strip foundations is fiberglass reinforcement, resistant to aggressive influences; ASK is advisable to use only in lightly loaded pile-tape foundations, or with a small pitch of piles due to low rigidity characteristics of ASK. With a significant load on the structures, it is recommended to use combined reinforcement: in areas of pure compression and tension using ASK, and in bending zones - metal reinforcement.

Historically, lightweight foam concrete (LWFC) has been used in non-structural applications. However, low self-weight, insulating properties and fire resistance make LWFC an ideal construction material for residential infrastructure, if suitable mechanical properties of strength, stiffness and ductility, as well as durability can be assured. The development of LWFC for structural use has created a need for a structural system that harnesses these beneficial material properties. In this paper a LWFC walling system is proposed, tested and analysed with finite elements. Results of quasi-static monotonic pull-over tests as well as cyclic tests indicate that the proposed precast walling and connection system is likely to both provide predictable structural behaviour as well as adequate resistance for low-rise residential buildings in regions of low to moderate seismicity .

The article analyzes the current situation in Russian construction industry associated with the low innovation activity at all levels of construction sphere. Among the many reasons for the technological low innovative ability to technological change in construction industry, the authors outline reasons that might radically and positively influence the situation in domestic construction within the first half of the 21st century. The object of the study is the "construction system" concept, which is proposed to be identified as a main link of building innovations that promotes or, accordingly hinders construction objects production. When considering this concept, it becomes obvious that the critical link of innovation is concentrated in the concept of "structural framework" and related technologies for the production of construction objects. It is concluded that the main obstacle to the construction industry innovative development is the conservatism of building frames structural solutions and the corresponding technologies of the construction systems which are oriented to multi-storey housing construction and the main priorities of such construction are concentrated in mega-cities. The requirements for living environment, architectural diversity, residential building layouts, «green building» principles, energy efficiency, economy and internal comfort of housing are being raised. The paper emphasizes that existing building systems, especially in megacities, is not able to solve demographic problems and promote a healthy and safe life for people. The authors suggest that in the near future the turn to other priorities of housing construction and the transition to a new technological order with the help of industrial innovative low-rise residential construction systems for development of the Eurasian space of the country on the "linear city" concept base.

The article considers existing and promising systems for the construction of slabs in low-rise buildings using stay in place (SIP) formwork. The main conditions for using these formwork systems are described and the disadvantages of existing structures are highlighted. Using the example of previously patented inventions, various trends in the development of formwork systems are revealed. The article deals with precast concrete structures of fixed formwork, modular structures of fixed formwork, various types of connections. Variants of fixed formwork with different types of installation and delivery of concrete mix, made of different materials and shapes are considered. The main individual features of each type of invention are highlighted, on the basis of which assumptions are made for the development of these systems. Based on the results of the analysis, the article offers technical requirements and a brief description of a promising formwork system for the construction of floors of low-rise buildings in cramped conditions.

Timber construction and fire safety are two terms which often lead to discussions, especially if it concerns multi-storey timber buildings. The scientific investigations presented here demonstrate the extent to which the use of a timber facade provides sufficient fire safety for people and the environment. Research work on prefabricated timber frame facade systems is carried out at the Department of Timber Construction at University of Innsbruck. The investigations are performed in three steps. Step 1: Typical fire exposure of buildings, building classes, requirements of high-rise buildings (>22 m fire escape level) and the properties of the materials in question are investigated. Special attention is given to the use of sustainable and ecological materials. Step 2: Performing reaction to fire tests and fire resistance tests with various materials and constructions which are included in classification reports. For this facade system also a connector system and a specific joint design for easy mounting was developed in a PhD thesis. Step 3: This facade element is tested for its suitability for its use in high-rise buildings. In fire tests is shown that the wooden substructure in the facade does not contribute the fire during a certain time. So the ban of inflammable materials in high-rise buildings could be mitigated. The scientific results show that the use of timber in prefabricated facade elements can meet the required criteria.

There are many passive energy dissipating devices designed to dissipate earthquake energy in a structure. Metallic yielding dampers is one of these devices which are very efficient as they dissipate seismic input energy through hysteretic behavior. This research used ETABS software to analyze the performance of three metallic yielding dampers; X-shaped damper, Double X-Shaped and Comb Teeth Damper. The storey response data obtained from the analysis is storey shear. Each damper has three types of material; A992 steel, A36 steel and Aluminium. Concentrically braced steel frames with Chevron bracing were used and the dampers were placed in brace to beam orientation in each frame. The two types of frames analyzed were; low rise building with five storeys and a high rise building with twenty storeys. The site locations for both structures were in the region of California in the United States of America. The structures were analyzed by subjecting them to two earthquakes Loma Prieta and San Fernando as they were two of the major earthquakes that struck California in the nineties.

This study focuses on the energy performance of low-rise residential buildings and on the technological improvements required to improve their performance. As most low-rise residential buildings in Korea are old, they are being renovated to improve their energy efficiency. However, as renovations are expensive, the government intends to apply low-cost energy-efficient technologies that are currently in use as well as quantify their performances. To this end, low-rise residential buildings in villages were selected for the survey; among these, five buildings were evaluated for the application of energy-efficient technologies. Based on the survey, which included information on the actual energy consumption, the reliability of the simulation analysis was verified, and the effects of the technologies were evaluated. The survey focused, in particular, on the airtight performance of the implemented technologies, the efficiency of the heating equipment, and the insulation performance. Moreover, the performances were validated quantitatively by actual measurements. As a result, the energy saving for each technology were evaluated, and the corresponding annual savings were calculated. Finally, the payback period of the investment was evaluated using economic analysis.

Low-rise reinforced concrete (RC) frames with brick masonry infill walls up to five stories high have been used for housing construction in Nepal since the late 1980s. Many buildings of this type were damaged and/or collapsed in the 25 April 2015 Gorkha earthquake (M 7.8), even in areas characterized with moderate shaking intensity such as Kathmandu Valley. Due to inadequate design and/or construction of RC frame components, these buildings essentially behave like masonry shear wall structures with a shear-dominant failure mechanism. The paper presents the findings of a field survey of 98 RC buildings affected by the 2015 earthquake. The main objective of the study was to correlate the observed damage in the buildings using the modified European macroseismic scale (EMS)-98 and the wall index (defined as the wall area in the direction of shaking divided by the total building plan area above the level of interest). The results can be used to help establish recommendations regarding the required wall index for low-rise RC buildings in Nepal.

Reinforced concrete wall-frame mixed buildings have been widely used as a seismic force resisting system because walls and frames can play complementary roles in earthquake resistance. In conventional design procedures (e.g., per ASCE 7), the walls and frames in mixed buildings have often been analyzed and designed separately by assigning a specific portion of the design lateral load to each one. These conventional procedures may in part be a product of a bygone era when computerized structural analysis programs were not widely used. However, advanced structural analysis programs are currently available, which can easily simulate the walls and frames simultaneously, and even three-dimensionally. Korean structural engineers have taken advantage of those programs and typically design such mixed buildings without separating the walls and frames or assigning any particular required strength to each one. This new design method is simple and easy to conduct, but it does not exactly follow the conventional design process for a wall-frame interactive system, even though it still uses the same seismic design parameters (from ASCE 7). Therefore, this study has investigated the feasibility of the new design method. Target buildings for the study have reinforced concrete ordinary shear walls in low-to-medium-rise wall-frame mixed buildings, and specifically those with plans having fairly limited bays except for the ones with walls, which makes it difficult to separate the walls and frames. To investigate the performance of buildings designed by the simple new method based on elastic analysis, nonlinear static pushover and nonlinear dynamic analyses have been conducted as part of this study, and engineering demand parameters such as story drift and concrete compressive strain at the wall base have been examined. Results indicate that buildings designed by the new method have good performance even for very conservative failure criteria. However, they exhibited less satisfactory performance than those designed by the conventional procedure. This shortcoming could be compensated for by a slight decrease in the response modification factor, or by specifying a lower bound wall area ratio or an upper bound wall axial load ratio. In order for these options to be applicable, some additional study may be necessary, where a wider variety of prototype buildings are examined utilizing probabilistic approaches.

Residential buildings contributed 14% of Canada's greenhouse gas emissions in 2014, making this sector pivotal to climate change mitigation. In 2016, the provincial government of Ontario, Canada mandated a net-zero carbon standard for new “small buildings” by 2030, meaning the low-rise residential sector must undergo major changes to meet this target. Through an energy modelling analysis of a typical single-family home in Ontario, this study demonstrates the potential carbon emissions savings of different reduction strategies, including changes to the building envelope and mechanical system. The most effective strategies include increasing building airtightness, installing additional exterior insulation, and switching to an air source heat pump for heating and cooling. These strategies were then analysed based on the incremental cost above a house built to the building code baseline. In terms of cost per kilogram of carbon mitigated, the most efficient strategies are further insulating the basement, adding additional exterior insulation, and increasing the efficiency of the heat recovery ventilator. Finally, a policy discussion demonstrates that carbon reductions implemented at the design stage must be verified and monitored post-occupancy using policy tools such as energy reporting and small-scale performance studies.

Previous studies have observed clear interference effects and differences in response from a building group against an isolated building. This study conducted numerical simulations for low-rise buildings under wind load to investigate the mean wind-induced interference effects between the buildings. The primary purpose is to reveal the characteristics of wind pressure distribution on gable roof of low-rise building considering interference effects such that practical wind-resistant design methods and measures can be proposed. Various arrangement modes, arrangement distances and wind direction angles were considered based on the Reynolds Stress Model (RSM) that was verified by a wind tunnel test. The results show that the strongest mean wind-induced interference effects occurred on the cornice of the interfered building for two of the same low-rise buildings. With regard to the arrangement of low-rise buildings, the tandem arrangement yields the largest effects, followed by the staggered arrangement and then the parallel arrangement. For the regular group of low-rise buildings, larger interference effects occurred on the roof of low-rise buildings that were located on the corners or outer parts of the groups.

With the aim of both reducing environmental footprint and improving technological properties, several construction materials have been successfully manufactured using using waste. However, the assessment has commonly been based on comparing technological behaviors, while the overall assessment of the so made building has been commonly overlooked. Thus, this papers shows the energy and mechanical performance of buildings with same structure design, building shape and envelopes characteristics but with different types of infill walls (IWs) which have been modelled by considering traditional materials (i.e. adobe and perforated fired clay bricks) and eco-materials, such as adobe and bricks made by using up to 10% and 17.5% of biomass bottom ashes, respectively. Building models have been designed in accordance with building codes, in terms of seismic and energy savings criteria. In addition, residential (RB) and non-residential (NRB) uses have been also considered for calculations. IWs had in all cases similar equivalent thermal transmittance, achieved by varying the air gap length between layers in order to establish a common comparative framework. Otherwise, IWs showed a different thermal capacity depending on used material within the wall construction. The analysis concluded that the mechanical behavior was similar in all cases, regardless the excess of weight added by adobes. Besides, in low height buildings the increasing of stiffness possesses an advantage for lateral loads resistance. In addition, by using adobe with ashes, 5% of equivalent CO2 footprint (i.e. from cradle to gate) and 4% of energy consumption may be saved. These savings must be even lower when the entire life cycle is considered, since adobes may be easily collected and reused without any treatments while fired clay bricks require further treatments.

This work describes the behaviour of a vertical axis Savonius Wind Turbine (SWT) in Four-way lane highways during South-West and North-East monsoons. A vertical axis SWT was designed and fabricated using low-cost materials. Starting behaviour of the SWT was studied by measuring and calculating the starting torque coefficient. The proposed SWT's cut-in speed was achieved at a velocity of 3.5 m/s. Experiments were carried out on a four-way lane highway through the placement of turbine at two different positions (middle and sides of the highway). Also, the experiments were repeated during different monsoons to understand the behaviour under different wind directions. Error analysis was performed on the data obtained by considering possible measurement errors and instrument accuracies. The obtained experimental data clearly illustrates that the SWT's nominal rotational speed varies at different monsoons, when located at the sides of the road. From the data analysis, it can be understood that the wind directions play a key role for harnessing maximum amount of energy in highway wind-energy generation. Maximum augmented rotational speed of around 64% was achieved by placing the SWT at the median of Four-way lane highways in different monsoons.

Wind-driven rain (WDR) intrusion in buildings during hurricanes often leads to significant damage to building interior and contents, causing major losses. Many buildings in hurricane-prone U.S. coastal states are fitted with soffit vents with louvers that are designed to close during high winds and reduce rain intrusion. This paper focuses on the topic of WDR intrusion through soffit vents and, in particular, studies the effects of louvered soffit vents on (i) reduction of water intrusion, and (ii) overall aerodynamic loading of buildings’ roofs. A gable and a hip roof building retrofitted with open and closed vents were tested at the Wall of Wind (WOW) experimental facility. WDR intrusion studies were carried out only on the hip roof building, while wind pressure distributions were estimated for the gable and hip roof buildings. Results from the WDR intrusion study indicate a marked reduction in water intrusion for the closed vent roofs. Moreover, the net mean and peak pressure coefficients for the closed vent roofs are reduced in magnitude (less suction) compared to the open vent roofs. Future research is recommended to study the effect of different vent sizes and locations, besides considering other roof types (e.g. mono-slope).

Summary This article examines the use of rocking steel braced frames for the retrofit of existing seismically deficient steel building structures. Rocking is also used to achieve superior seismic performance to reduce repair costs and disruption time after earthquakes. The study focuses on low-rise buildings for which re-centring is solely provided by gravity loads rather than added post-tensioning elements. Friction energy dissipative (ED) devices are used to control drifts. The system is applied to 2-storey and 3-storey structures located in 2 seismically active regions of Canada. Firm ground and soft soil conditions are considered. The seismic performance of the retrofit scheme is evaluated using nonlinear dynamic analysis and ASCE 41-13. For all structures, rocking permits to achieve immediate occupancy performance under 2% in 50 years seismic hazard if the braces and their connections at the building's top storeys are strengthened to resist amplified forces due to higher mode response. Base shears are also increased due to higher modes. Impact at column bases upon rocking induces magnified column forces and vertical response in the gravity system. Friction ED is found more effective for drift control than systems with ring springs or bars yielding in tension. Drifts are sufficiently small to achieve position retention performance for most nonstructural components. Horizontal accelerations are generally lower than predicted from ASCE 41 for regular nonrocking structures. Vertical accelerations in the gravity framing directly connected to the rocking frame are however higher than those predicted for ordinary structures. Vertical ground motions have limited effect on frame response.

Increased frequency and intensity of coastal storms has renewed interest in the structural performance of coastal low-rise residential homes. Post hazard surveys indicate connections that form the load path from sheathing to framing to foundation play a pivotal role in the failure modes of these non-engineered structures. Nonlinear spring elements are a common means of modeling nailed connections for structural analysis based on experimentally observed behavior. Due to complex connection behavior, three independent springs are usually defined to consider 3D translational displacements. This common approach may introduce error in large displacement analyses due to independently defined directional spring properties. After a brief discussion of issues encountered with nonlinear spring element connection modeling schemes, an equivalent parameterized beam connection model is proposed to characterize softening-type connection behavior. Comparison analyses between the equivalent parameterized beam connector (EPBC) and equivalent nonlinear spring connector (ENSC) are carried out using 1D and 2D single element examples as well as 3D panel models. This new connection modeling scheme could greatly reduce meshing efforts in large models and provide more accurate solutions in critical areas of the structure such as corners and edges by coupling the axial and transverse connection responses.

Given the significant role of internal pressures in the wind-induced loading of low-rise buildings, their correct estimation is critical for the accurate determination of the net (external plus internal) wind effects. This paper presents results of an investigation conducted to study the effect of wind-induced internal pressures on structural frame forces on low-rise buildings with single or multiple dominant openings. Models from the National Institute of Standards and Technology (NIST) aerodynamic database with internal pressure measurements were used. Large-scale experiments were also conducted in the Wall of Wind (WOW) facility at Florida International University (FIU) using a model with multiple openings. Calculations of frame forces were performed using the Database-Assisted Design (DAD) methodology. It was found that internal pressure significantly increases the forces induced by wind with the most unfavorable direction on the frames located close to the openings. However, its effect on the frames located away from the openings was smaller. Effects of internal pressure also varied between different cross-sectional locations of the same frame, depending upon the correlation between forces induced by external and internal pressures. For the highest net frame forces, the reduction factor applied to the response induced by internal pressures, that accounts for the imperfect correlation between the external and internal pressures, was found to be approximately 0.85. Comparison between frame forces calculated using experimentally measured internal pressures and their counterparts evaluated by using ASCE 7–10 provisions for internal pressures showed that the latter result in unconservative estimates of frame forces in both enclosed and partially enclosed buildings. An additional significant result is that the ASCE 7 classification of buildings with equally sized windward and leeward openings as enclosed buildings can lead to the underestimation of net frame responses. It is therefore proposed that this classification be changed to reflect the appropriate internal pressure effects.

The unsatisfying performance of light-frame low-rise buildings under hurricane winds is a long-standing issue. Most past research effort has been made in creating a wind pressure database using advanced testing facilities, studying “cutout” subassemblies (i.e., roof subassemblies/sheathed shear walls) without considering the imparted influences of the whole system, analyzing load transfer mechanisms within full building models in the linear range, and quantifying building performance for the purpose of estimating economic losses. What still remains unclear is the contribution of some key factors, such as the simplified spatial-temporal varying wind loads, the resolution of numerical models, and the building component capacities, with large uncertainties, to the ultimate building performance. This paper aims to review the state-of-the-art research of four related disciplines that may contribute to a rational building performance assessment from an engineering perspective. Hurricane hazards, public wind pressure databases, and design wind loads are reviewed to indicate the importance of parameters other than wind speed to the building performance. The evolution of the low-rise building FE modeling is summarized with an emphasis on the connection modeling as well as their comparisons with experimental measurements. The quantification of the building performance is discussed by using stochastic finite element modeling techniques. At last, areas requiring future studies are identified to fill knowledge gaps.

The Tuned Liquid Damper (TLD) is a passive supplemental damping device which can be used for effective mitigation of wind and earthquake induced responses. The use of TLDs in low to medium rise reinforced concrete (RC) buildings is a less explored area and needs to be investigated. The objective of the present study is to evaluate the applicability of flat bottom rectangular TLD to low-rise buildings using normal water and a sugar–water solution (higher density then normal water). Also, in flat bottom rectangular TLD the circulation of the liquid continues even after the excitation stops, which is detrimental to the structure and this issue has been addressed here. For this purpose a series of tests has been carried out for parametric study on such TLDs, varying the ratio of water depth to length of tank, excitation frequencies and amplitudes. The applicability of TLD in RC building has been investigated using a three-storey 1/4 scale RC building model. The model has been tested in a shake table. ...

The applicability of the N2 method, the modal pushover analysis (MPA) and an adaptive pushover analysis method are investigated for estimating the peak seismic responses of unreinforced masonry buildings with flexible diaphragms. The performance of nonlinear static procedures are compared against the nonlinear time-history analyses of three low-rise building models with various levels of stiffness eccentricity, type of failure mechanisms of piers (rocking or shear), and a range of diaphragm stiffness representing timber floor and roof systems. The results indicate that the MPA is unsuitable for unreinforced masonry buildings with flexible diaphragms, if the building response is shear-dominated. The adaptive method provides the most accurate estimates when the diaphragms are relatively stiff. When the diaphragms are relatively flexible, none of these methods can provide accurate predictions of peak seismic demands. However, conservative results may be obtained with the N2 method, by taking the envelope of pushover analyses carried out using the force distributions proportional to the uniform and linear displacement shapes along the height of the building. The present study has also identified the most suitable parameters/methods for the use of various nonlinear static procedures, such as the location of the control node used in the N2 method and the modal combination rule used in the MPA, for unreinforced masonry buildings with flexible diaphragms.

Sliding foundation is a technique to suppress seismic loads applied to structures. There are many studies showing that sliding foundations are efficient especially for low rise buildings; however, most of them have ignored the effects of vertical components of the earthquake records on the behavior of such bases. This paper focuses on influences of sliding foundations on seismic behavior of low rise buildings, for real cases. For this purpose, vertical component of earthquakes is considered as well as inherent properties of foundation material such as coefficient of restitution (COR). Furthermore, variation of friction coefficient during the earthquake is considered. COR is utilized to consider bouncing of the structure after separation of the foundation, occurred for extreme downward vertical accelerations (greater than gravitational acceleration). Variation of friction coefficient is considered based on a new study, showing that the coefficient of friction depends on instantaneous amplitude and frequency of the vertical excitation. The obtained results show that vertical component of earthquake affects the behavior of the sliding base substantially. It is also demonstrated that providing material for the sliding base with higher COR is advantageous in decreasing structural acceleration response. Furthermore, the coefficient of friction is really lower than the regularly assumed values and, therefore, leads to smaller structural acceleration response but mostly greater residual displacements.

This paper presents the assessment results and structural retrofitting of SPS Building. The building is a three story reinforced concrete structure with a mezzanine floor for a storage. The building was an office building with a live load of 2.5 kN/m2 and then the building function changes to be an industrial building with a live load of 10 kN/m2. The existing concrete and rebars tensile strength, structural member dimensions and configuration were assessed before structural analysis and redesign were done using a commercial software. It is found that the average concrete strength is about 11 MPa and most of existing structural members are less flexure and shear capacity. Therefore, an external flexure and shear strengthening using external bolted steel plates were applied to those members with grouting materials to fill the gaps between the steel plate and existing structural members. A strength evaluation using direct loading with a maximum water depth of 1000 mm over an area of 60 m2 to represent the live load of 10 kN/m2 was conducted to ensure the retrofitting method works well. The test results show that measured deflections of beams and slabs are still less than the maximum deflection limits. This indicates that the strengthening system using external bolted steel plates can improve the member capacity to support the new design loads.

Frame systems are the preferred structural systems in most seismic regions, where they are sometimes also combined with braces or walls. On the other hand Chile, one of the most seismically active countries in the world, is an exception to this practice. Any Chilean residential building higher than 5 stories is almost completely made up of reinforced concrete shear walls. Surprisingly, only 2% of the residential building inventory subjected to the 2010 Chile earthquake (M w 8.8) suffered severe damage, even though many structures were affected by ground accelerations larger than those prescribed in the Chilean seismic design code. This observation suggests that there is a large (and unintended) overstrength in this type of buildings. In a previous study, the authors showed that some of the traditional sources of overstrength mentioned in the literature could explain the lack of damage in low rise buildings but not in taller structures. Motivated by this observation, representative tall buildings were reanalyzed using more realistic models (e.g., flexural capacity of the walls assessed by fiber models) in order to get more insight into their actual seismic capacity. Two actual buildings of 17 and 26 stories that survived with no damage the 2010 Chile earthquake were analyzed by response history analysis. Results show that consideration of wall flanges (usually omitted in practice) cannot explain the lack of damage. On the other hand, it is observed that good performance might be a consequence of possible foundation uplift. Finally, the analyses also suggest that, even when there is no damage, elastic analysis has limitations to reproduce the actual observed behavior.

In the urban residential building stock, a major proportion is constituted by low-rise individual buildings. In addition to cost, quality and duration, energy consumed for the project needs to be accounted in the decision making process. Minimizing the cost of construction without compromising on the architectural and structural requirements is the primary objective of the residential buildings of stake-holders, especially the owners. The choice of structural system and the materials used for construction play a crucial role in this effort. This means that the use of expensive and/or voluminous materials such as cement, steel, masonry etc. is optimized. This could lead to significant reduction in embodied energy as well, if the choice of the structural system is prudently made. In this paper, an attempt has been made to quantify the cost and embodied energy benefits for a low-rise residential building by choosing two different structural systems, namely moment resisting framed (MRF) construction system and the partly load-bearing (PLB) system. The influence of choice of materials, contributing to reduction of cost and/or energy is discussed. It is clearly noticed that, when the structural system is re-configured as a PLB system from the existing MRF system there is significant reduction in cost and embodied energy without changing the architectural form.

A fragility analysis is conducted for loss of roof cladding for low rise metal-clad industrial buildings located in non-cyclonic regions of Australia. The stochastic analysis includes possible component and connection failures, load redistribution based on progressive failure, spatial distribution of wind load, and internal pressure variation caused by roof sheeting failure. This spatial and time-dependent reliability analysis will enable fragility curves to be developed that relate likelihood and extent of roof cover damage with wind speed. Industrial buildings representative of new construction in the Australian cities of Brisbane, Sydney and Melbourne are considered. Fragility functions are proposed for industrial buildings designed and constructed to existing codes, and also for improperly designed or constructed buildings where a roller door or other dominant opening prematurely fails during a storm for a building designed as nominally sealed. It was found that damage risks double if a roller door or other dominant opening prematurely fails during a storm.

Multi‐storied building construction is increasing rapidly throughout the world. Tall buildings more effectively utilize land compared to low rise building. As the height of building increases the importance of lateral load resisting system becomes more relevant than gravity load resisting structural system. Many structural systems are recently introduced to improve the structural performance of tall buildings. Hexagrid system is one among them. Hexagrid system consists of multiple hexagonal grids at the exterior perimeter of the building. It resists both lateral loads and gravity loads by axial stress of their members. The members simply act in tension or compression and show no bending which reduces the need of steel. The paper presents the comparison of different patterns of hexagrid system.

Currently, Russia is in dire need of a large-scale expansion of the construction of low-rise residential buildings, both in urban areas and in rural areas. As of today, various technologies are used in low-rise construction, including those with the use of wood. The feasibility of expanding the choice of wood as the main building material is due to a number of known advantages over other building materials. However, upon a detailed examination of the territory of the Russian Federation as a whole, it should be noted, despite the fact that our country has huge reserves of forest resources, forests are distributed over the territory of our country extremely unevenly. In order to increase the efficiency of wood consumption for the needs of low-rise housing construction, it is proposed to improve the panel construction technology from wood and wood materials by simplifying the structural scheme of the building, increasing its spatial rigidity and reducing the labor intensity of installation. This improvement is realized due to the organic combination of the advantages of frame and panel technologies with the elimination, if possible, of their main structural, installation and operational shortcomings. The proposed technology for erecting a building from wooden panels makes it possible to simplify the design scheme, increase its spatial rigidity and reduce the labor intensity of installation, which gives impetus to further improvement of design solutions for residential buildings, industrial buildings and public facilities designed on the basis of wood and wood materials, ensuring the rational use of material in sparsely wooded areas of our country.

The article presents a program of scientific and practical research on the assessment of “green” technologies in wooden low-rise housing construction in the field of energy efficiency and resource conservation. The objects of research are two identical experimental buildings built in 2020 in Murmansk and Petrozavodsk using different technologies of wooden housing construction and various thermal insulation materials. Attention is focused on assessing the factors affecting the energy efficiency class and the internal microclimate of a wooden building, taking into account the changing environmental conditions and operating modes of buildings in cold climates. The stages of the study were determined, the tasks for each type of experiment and the expected results were formulated. Methods fixed in the regulatory documents of the Russian Federation are considered as the main ones. A method for monitoring the parameters of the internal microclimate, environment and temperature and humidity in the layers of the enclosing structures of model objects is proposed and implemented. The implementation of the research program will allow assessing the influence of the factors under study on the energy efficiency class of a wooden building and developing recommendations for the design, construction and operation of low-rise wooden buildings in a cold climate, taking into account the criteria of “green” construction.

Seismic risk assessment of unreinforced masonry (URM) buildings is an important process for seismic retrofit of essential facilities located in the central and southern United States (CSUS), as more than 30 % of facilities there are low-rise URM buildings. Although HAZUS, the current loss estimation package for natural hazards, provides a set of fragility curves for such structures as an essential tool for conducting seismic risk assessment, seismic performance level variation due to geometric characteristics is not explicitly considered. This study investigates the effect of geometric variation of low-rise URM structures on seismic fragility assessment. Utilizing URM building inventory information within the CSUS region, variables that describe the physical shape of URM structures are identified. A simplified composite spring model developed for URM structures is then utilized to monitor nonlinear seismic behavior. Finally, seismic fragility curves corresponding to various shape configurations of URM structures are developed and compared. The analysis confirms that the length of out-of-plane walls and the number of stories in URM buildings have significant effects on seismic risk. An increase in the wall length or the number of stories makes URM buildings more vulnerable. On the other hand, the perforation ratio does not significantly affect seismic performance. It is suggested that using a single set of fragility curves is not adequate for seismic risk assessment of low-rise URM buildings unless geometric variation is considered explicitly. In addition, comparing the fragility curves developed in this study with HAZUS data, it is clear that the seismic vulnerability of low-rise URM is underestimated in HAZUS for lower limit states and overestimated for higher limit states.

This paper proposes a method for preliminary Performance-Based Seismic Design (PBSD) of low-rise structures protected with Buckling-Restrained Braces (BRBs). It is assumed that a frame structure protected with BRBs, termed as a dual structure, is rationally represented by a dual single-degree-of-freedom (SDOF) oscillator whose parts yield at different displacement levels. The formulation of the method is presented for SDOF structures. This simplification is validated using a case study example. A comparison of the responses between conventional and dual structures shows that, when designing dual structures, the common practice of using conventional design spectra may lead to biased designs. One of the main advantages of the method is that, during its application, information useful for preliminary and quick assessment of structures is generated, facilitating the application of the PBSD philosophy. A case study example is conducted to show its applicability and its potential for preliminary assessment of structures. Regarding its limitations, the method is valid for low-rise regular buildings with rigid in-plane diaphragms, and whose dynamic response is dominated by their fundamental mode of vibration.