Single-story Building Research Articles

Performance characterization of a wireless sensors network system (WSNS) for measurements of hurricane wind effects on structures

This paper presents a new wireless sensors network system (WSNS) designed for high-resolution absolute pressure measurements, wind speed, and direction. The system is tailored to assess the impact of hurricane winds on residential structures, both in laboratory settings and field environments. Importantly WSNS stands out for its unique ability to provide waterproof, surface-mounted external pressure measurements. The system's performance is evaluated during deployment on a full-scale house model at the Wall of Wind facility. The WSNS sensors were installed on different surfaces of a single-story residential building model. The sensor locations mirrored the locations of surface pressure taps connected to a Scanivalve differential pressure measurement system. Due to the size and shape of the WSNS pressure module, a casing effect was observed, which may result in pressure offsets under certain wind speeds and directions, depending on the sensor's location and the conditions, including dry and light rain (50 mm per hour). The comparison between WSNS and Scanivalve indicates that the sensor's casing geometry does not cause significant differences in the time-averaged measurements for low-turbulence regions. Conversely, this is not true for high-turbulence regions, which should be marked for future deployments using smaller surface-mounted pressure taps.

Microclimate Effect on Cooling Energy for Buildings in Hot, Humid Climates: A Comparative Analysis of Shaded and Unshaded Environments

This paper explores the influence of microclimates on changes in air temperature and the often-overlooked aspect of their effect on energy savings across varying microclimatic conditions. The study compares the cooling energy requirements of two identical single-story buildings in distinct microclimates: one characterized by concrete ground devoid of shade and the other featuring soil ground with tree shade. Climatic environmental data were collected over 15 days in the concrete-exposed field and shaded area beneath the trees to conduct the investigation. These datasets were input into EnergyPlus 9.6 to model the energy demands and consumption of buildings subject to the specified climatic conditions. The validation of the simulated model against actual energy demand data from a classroom building demonstrated agreement. The findings reveal notable differences in air temperature, with the shaded area experiencing temperatures 0.8°C to 8.0°C lower than the concrete-exposed monitoring location. The building in the tree-shaded microclimate exhibited a lower peak cooling load than its concrete-exposed counterpart, resulting in a 35% reduction in the electrical energy requirements for the air-conditioning system. The study recommends implementing 0.08-m polyurethane insulation for the building walls and roof to equalize the energy demand and consumption of the concrete-exposed building with that of its shaded counterpart. Furthermore, building design in shaded areas can maximize the window glass area while consuming less energy than buildings on concrete-exposed grounds. The study advocates leveraging the microclimate associated with surrounding buildings in the design process to enhance the overall energy savings.

Lateral-torsional buckling investigation of multi-tiers eccentrically braced frames with shear link beam

Multi-tiered braced frames (MTBF) are a type of braced frames with two or more tiers of bracing or bracing panels between horizontal diaphragm levels or locations of out-of-plane support, along with a beam at every tier level. They are commonly used in tall single-story building structures when it is not practical to use single bracing members spanning from roof to foundation levels. Additionally, they find application in multistory buildings with tall story heights. In this paper, lateral-torsional buckling of beams in a new type of MTBF called multi-tiered eccentrically braced frames (MT-EBF) is evaluated. This structural system is not mentioned in any of the current code and seismic criteria have not been provided. The main different of this system with eccentrically brace frame is the lack of laterally supported in the intermediate beam. Also, in industrial buildings that need architectural openings, this system is more useful than concentrically braced frame. For this purpose, the seismic behavior of four different MT-EBF with one and two tiers, along with two different configurations for the connection of braces to the beams, is studied. In the first configuration, the braces are connected to the beam using a gusset plate, and in the second configuration, the braces are directly connected to the beam using full penetration groove weld. The results of the numerical study indicate that in the first configuration, lateral-torsional buckling occurs in the intermediate beams, and the connection of the gusset plate to the beams lacks the necessary stiffness to prevent lateral-torsional buckling. However, in the second configuration, lateral-torsional buckling of the intermediate beams is prevented, and the connection of the braces to the beams has the adequate stiffness to prevent lateral-torsional buckling.

An extended model for evacuation considering pedestrian behavior of emergency avoidance in the earthquake situation

In earthquake situations, emergency avoidance is an important way to ensure the life safety of pedestrians. To study the behavior of emergency avoidance of pedestrians in a disaster situation, an extended cellular automata model for pedestrian evacuation is established according to the real video records. The concepts of “avoidance rate” and “avoidance time” are introduced to describe emergency avoidance behavior. The trampling behavior of pedestrians is also considered in the model, which draws on the concept of repulsive force in the social force model. Taking into account both evacuation time and stampede probability, the total risk index is used to describe the overall evacuation risk. The single-story teaching building was used as an evacuation scene. Parameters affecting the whole evacuation process and overall evacuation risk such as avoidance rate and avoidance time were analyzed. What’s more, seven evacuation strategies were discussed in detail. The study shows that reasonable arrangement of pedestrian evacuation with avoidance rate and avoidance time in a certain range can reduce congestion and improve the safety of evacuation and the evacuation time will not increase obviously. This work can provide theoretical references for evaluating the overall risk of evacuation and also provide technical support for formulating evacuation strategies under earthquakes.

Seismic Performance of a Single-Story Timber-Framed Masonry Structure Strengthened with Fiber-Reinforced Cement Mortar.

Timber-framed masonry structures are widely used around the world, and their seismic performance is generally poor. Most of them have not been seismically strengthened. In areas with high seismic fortification intensity, there are great potential safety hazards. And it is urgent to carry out effective seismic reinforcement. However, due to the complicated construction process of the existing reinforcement technology, the poor durability of the reinforcement materials, and the significant disturbance to the life of the original residents, an efficient single-story timber-framed masonry structure reinforcement technology suitable for comprehensive promotion and application has not been explored. In this paper, a fiber-reinforced cement mortar (FRCM) material was proposed. A 1/2 scale model of a single-story timber-framed masonry structure was taken as the research object. The method of strengthening a single-story timber-framed masonry structure with FRCM layer was adopted. And the shaking table test of the model before and after reinforcement was carried out in turn. The dynamic characteristics, failure modes, acceleration response and displacement response of the FRCM layer-strengthened structure were analyzed through comparisons of the two cases. The experimental results showed that the FRCM layer significantly improved the seismic performance of the seismic-damaged single-story timber-framed masonry structures. The X- and Y-direction natural frequencies of the model structure were increased by 31.30% and 30.22%, respectively, after the structure was strengthened with FRCM. During a rare eight-degree earthquake, the inter-story displacement angles in the X- and Y-direction of the unreinforced model reached 1/98 and 1/577, respectively, and the structure was destroyed, while the inter-story displacement angle of the FRCM-reinforced model was only 1/2 of that the unreinforced model. During a rare nine-degree earthquake, the X-direction inter-story displacement angle of the model strengthened with FRCM reached 1/78 and the Y-direction inter-story displacement angle reached 1/178. At this time, the reinforced model structure was destroyed, but there was no collapse of the structural components, which met the seismic design objectives of "operational under the design minor seismic intensity, repairable damage under the design seismic precautionary intensity, and collapse prevention under the design rare seismic intensity", which proved that the FRCM layer was an effective and feasible way to strengthen the existing single-story wood-masonry rural building.

Bayesian structural model updating with multimodal variational autoencoder

A novel framework for Bayesian structural model updating is presented in this study. The proposed method utilizes the surrogate unimodal encoders of a multimodal variational autoencoder (VAE). The method facilitates an approximation of the likelihood when dealing with a small number of observations. It is particularly suitable for high-dimensional correlated simultaneous observations applicable to various dynamic analysis models. The proposed approach was benchmarked using a numerical model of a single-story frame building with acceleration and dynamic strain measurements. Additionally, an example involving a Bayesian update of nonlinear model parameters for a three-degree-of-freedom lumped mass model demonstrates computational efficiency when compared to using the original VAE, while maintaining adequate accuracy for practical applications.

Innovative hysteretic device for seismic retrofit of single-story RC precast buildings

In the last decades, many efforts have been made by the scientific community and technicians in order to develop effective and practical retrofit approaches for industrial RC precast buildings. Given the aftermath of recent earthquakes, which identified structural and non-structural dry joints as the highest source of seismic vulnerability, the majority of the retrofit techniques involves interventions at the connections level. The primary function of creating an adequate constraint is nowadays frequently associated to energy dissipation, allowing to both remove the major building weakness and decreasing the seismic demand in terms of elements’ stresses and deformations. In the following, a novel metallic hysteretic device intended for beam-to-column connection retrofit is presented. An existing one-story RC precast building with friction beam-to-column joints is considered as case-study structure; mechanical properties of the device are calibrated, and its effectiveness validated though nonlinear dynamic analyses. The proposed device demonstrates its ability in both restrain the relative displacement between structural elements and dissipate an adequate amount of input energy coming from ground motions, preventing structural damage. A comparison with the same device without hysteretic properties, i.e., a non-dissipative device, is also carried out, highlighting the benefits in using the hysteretic version.

Primary Energy and Carbon Impacts of Structural Frames with Equivalent Design Criteria: Influence of Different Materials and Levels of Prefabrication

This study aims to analyze the life-cycle primary energy and climate impacts of structural frames, paying particular attention to the design and prefabrication of different structural materials. The study considers an existing single-story office building with a composite concrete–steel structure and compares it with two functionally equivalent structures, i.e., a conventional reinforced concrete structure and a conventional steel structure. The existing building is located in San Felice sul Panaro, Italy. This study integrates dynamic structural analysis and life-cycle assessment (LCA). The study finds that the use of different materials can reduce the life-cycle primary energy use and CO2-eq emissions by up to 12%. Furthermore, the benefits derived from the recovery and recycling of materials can reduce the primary energy use and CO2-eq emissions by up to 47% and 36%, respectively. The prefabrication of structural elements can also reduce the primary energy use and CO2-eq emissions in the construction stage. A sensitivity analysis considers changes in the electricity supply system and shows that the primary energy and CO2-eq emissions due to prefabrication decrease when assuming marginal electricity based on renewable energies. This analysis supports the development of sustainable structural design to meet the standards concerning the whole-life-cycle carbon emissions of buildings.

Quality of Harvested Rainwater from a Green and a Bitumen Roof in an Air Polluted Region

A one-year study was conducted to evaluate the impact of air pollution and roof coating on runoff quality. An existing 440 sq meter bitumen roof of a single-story building was coated with an extensive green roof layer on one half. Rainfall and runoff samples from both roofs were collected during 11 rainfall events after the separation of the first flush. The study monitored several key parameters, including pH, electrical conductivity (EC), turbidity, chemical oxygen demand (COD), ammonium nitrogen, nitrate nitrogen, and phosphates. The study revealed that both types of roofs altered the rainfall quality, but the changes caused by the green roof were more substantial. Although the retention of runoff from green roofs has a widely acknowledged positive impact on collecting systems, our study shows that green roofs also result in a 7.5-fold increase in COD concentrations, a 5.4-fold increase in the sum of ammonium and nitrate nitrogen, and a 2.3-fold increase in phosphates compared to bitumen roofs. A clear link between the quality of rainwater/runoff and air pollution was not established. The study's findings will aid in the development and management of local rainwater harvesting systems and enhance global understanding of the primary quality parameters of various roof types, particularly in regions with air pollution. Doi: 10.28991/CEJ-2024-010-05-015 Full Text: PDF

Seismic Risk Assessment of Built Environment in the Himalayan Foothill City of Dehradun, Uttarakhand

Himalayan foothill city of Dehradun in Uttarakhand state is located in a tectonically active region and is prone to earthquakes. The growth of Dehradun city is analysed using high resolution remote sensing datasets in the current study, with a focus on its vulnerability to seismic risks for single and double storey structures as the city is predominantly made up of low-rise structures. Analysis shows that 10% of urban expansion has occurred in spectral acceleration zones that are vulnerable to double-storey buildings, while 38% of urban expansion has happened in spectral acceleration zones that are vulnerable to single-storey buildings. The proposed land use as per Dehradun Masterplan 2041 is examined with reference to National Earthquake Hazards Reduction Program (NEHRP) for seismic regulating provisions. It is emphasized that the intended land use is incongruous in areas with higher spectral acceleration zones since it comprises structures with higher occupancy and the amenities required during post-earthquake rehabilitation. On the other hand, the open spaces are more appropriate in these locations, which will lessen susceptibility as the influence of seismic forces can be sufficiently attenuated. The present study, thus highlights the significance of including seismic risk information in urban planning processes in order to ensure resilient cities.

Parameter optimization of vibration control system for adjacent building structures based on negative stiffness inerter damper

Building structures are subjected to strong earthquakes, which result in lateral collisions between them. Such collisions often cause severe structural damage and exacerbate the seismic hazard risk of building structures during earthquake events. This paper discusses the application of vibration control devices based on negative stiffness inerter damper in single-story adjacent building structures. The dynamic equations of the vibration control system containing different types of negative stiffness inerter damper under seismic excitation are established as a unified model. The H2 norm theory and Monte Carlo pattern search method are used to optimize the design parameters to improve the vibration control performance of the system, and the dynamic characteristics of the system are investigated. The results demonstrate that attaching negative stiffness inerter damper to adjacent building structures can effectively improve the overall seismic capacity reserve of the building and reduce the risk of collision of adjacent building structures; improve the robustness and stability of the system, and better reduce the displacement response of the building structure under seismic excitation. In addition, the potential of NSID-based vibration control devices to convert seismic energy into usable electricity has been investigated.

An Approach for Modelling Accidental Eccentricity Effects in Symmetrical Frame Buildings Exhibiting Semi-Rigid Diaphragm Behavior

The accidental eccentricity effect is specified, in earthquake codes, to account for the possible uncertainties in the mass and stiffness distribution of the structural system and the effect of the torsional component of the earthquake ground motion on the building. Türkiye Building Earthquake Code (TBEC-2018) considers the additional eccentricity effect only for the cases where rigid diaphragm behavior is provided in the slabs. However, in buildings with A2 and A3 irregularities or flexible diaphragms including insufficient strength and stiffness, the in-plane deformations and stresses on diaphragms may change the behavior of buildings under earthquake loads. In this study, a practical approach to be used in the equivalent earthquake load method was proposed to apply the accidental eccentricity effect on symmetrical frame buildings with semi-rigid diaphragms. The approach is based on distributing the total accidental torsion to the nodes as fictitious forces. Two numerical examples were presented. The first is a single-story precast industrial-type RC building, where the calculation steps of the procedure explained in detail. The building was modeled with both semi-rigid and rigid diaphragm assumptions, and a comparison of two modeling assumptions under accidental torsion was presented. Torsional irregularity factors obtained from building modeled by semi-rigid diaphragm assumption provided greater values with respect to those modeled by rigid diaphragm. This shows the significance of considering accidental eccentricity for semi-rigid diaphragms. The second numerical example, which is a RC concrete building, was used to validate the proposed methodology via finite element model (FEM) built-in algorithm. The obtained displacement demands by using the proposed methodology were very close to FEM results as a reference for the real solution. It is concluded from this study that the proposed methodology is reliable and can be used for modeling accidental eccentricity effects on symmetrical-plan buildings with semi-rigid diaphragms.

OPTIMAL SINGLE-STORY STEEL BUILDINGS UNDER HIGH LOADS

This paper presents the parametric optimization of single-story steel buildings subjected to high loads. In the parametric study, high loads of snow and wind are determined for different altitudes up to 3000 meters above sea level. The Alpine region and the Eurocode 1 standard are considered. The discrete mixed-integer non-linear programming optimization is performed for different altitude alternatives. The optimization model for the steel structure is developed and used. The mass objective function of the structure is subjected to dimensioning and deflection constraints defined by the Eurocode standards. The modified outer-approximation and equality-relaxation algorithm is applied. The optimal results obtained include the minimal possible mass of the structure, the optimal topology, the steel sections and the steel grade. In the case of a medium-sized single-story steel building, it was found that the structural mass increases by 2.7 times and the number of main portal frames increases by 80 % when the altitude of the building site is increased from 500 to 3000 meters above sea level. The optimal results clearly show how the structural mass and cross-sections increase with increasing load.

Regional climate change adaptation planning: a case study on single-story wooden-frame residential buildings vulnerable to hurricane winds in selected US coastal locations

The projected increase in sea surface temperature due to climate change is expected to substantially intensify future hurricanes. Wooden light-frame residential buildings are particularly vulnerable to hurricane damage, and their risk is expected to increase due to heightened exposure and intensifying hurricanes. Therefore, adaptation strategies need to be planned to reduce damage to such buildings while considering the impact of climate change on hurricanes. This study investigates the effectiveness of various climate change adaptation strategies for coastal wood-frame single-story residential buildings and demonstrates how these strategies can be planned. The study considers the four Representative Concentration Pathways (RCPs) proposed by the IPCC to investigate the impact of climate change on wind hazard and losses. Additionally, three locations in the coastal United States of varying sizes, exposure, and hurricane hazard levels are considered: Harris County, Texas; Mobile County, Alabama; and Miami-Dade County, Florida. The results show that the increase in wind speeds and losses will be non-linear with time. All considered adaptation strategies decreased losses, with some able to completely counter the increasing losses even under high emission scenarios. Investigating the effectiveness of adaptive measures can guide stakeholders in allocating funds and efforts for hurricane risk management and enhancing community resilience.

Floor Response Spectra of Single-Story Asymmetric Buildings

Floor Response Spectra of Single-Story Asymmetric Buildings

Reduction of additional pressure from ground construction on the subway escalator tunnel

The study considered options for reducing the additional pressure from the construction of a single-storey building on the underground structures of a deep shallow metro station. In the 3D formulation, the efficiency of the unloading «bridge» over the escalator tunnel was evaluated by the finite element method. It was found that the stiffer the grillage plate of the unloading «bridge», the more effectively the additional pressure from the building is transferred to the soils below the bottom of the escalator tunnel. However, in this case it is impossible to completely eliminate the additional pressure. In this regard, the option of creating an underground floor was considered. In this case, the weight of the selected from the excavation soil compensates the load from the building. The required depth of the basement floor was determined analytically, calculations were performed in characteristic sections on 2D models, and the operation of all structures in combination was considered on a general 3D model. Based on the results of the study, a rational algorithm was proposed for calculating the additional pressure from ground construction on underground subway structures.

Reliability analysis of single-story industrial buildings under wind load based on Monte Carlo simulation

Uncertain disasters such as typhoons can affect buildings. Single-storey industrial building is an important type of factory building. In this paper, the reliability of a single storey industrial building under wind load is studied by taking one typical factory in Hunan, China as an example. Firstly, finite element method is used to analyse the structure in the range of linear elasticity. Then, based on Monte Carlo simulation, the probability of failure of the structure under wind load is obtained. The results show that the probability of damage is relatively small, which is also in line with the fact that inland areas are not easily affected by typhoons. In order to obtain a deeper understanding of its reliability, the structural fragility curve considering the variability of steel strength is also studied. The results showed that the smaller the variability of the steel, the more beneficial it is for the reliability of the structure.

Water-related deterioration risk assessment for sustainable conservation of heritage buildings in the Forbidden City, China

A suitable hygrothermal environment is imperative for sustainably conserving movable and immovable cultural heritage. This paper proposes a combined method for quantitatively assessing water-related deterioration risks in heritage buildings, validated employing the Forbidden City in China, a UNESCO World Heritage site. The approach emphasizes combining hygrothermal coupled transfer simulation with conventional environmental monitoring for systematic risk assessments. Key findings include identifying predominant causes of year-round deteriorations of salt weathering, freeze–thaw damage, microorganism growth, and physical cracking. Secondly, it underscores the persistent dampness at the bottom, stemming from capillary rising in building foundations, rendering the present environment unsuitable for the conservation of single-story heritage buildings. Lastly, in the Forbidden City, significant deteriorations manifest just a few millimeters or centimeters beneath the surfaces of brick walls and floors. Suggested measures include reducing shallow groundwater and enhancing airtightness. This study establishes a scientific framework for deterioration risk assessment and sustainable cultural heritage conservation.

Reliable Tilt of Objects Subjected to Rectification and Located in Mining Areas

Abstract Mining exploitation of hard coal is conducted in the Silesian region in Poland. As a result, the post-mining void is formed which leads to non-uniform lowering of the ground level. Consequently, thousands of buildings are vertically deflected. This type of deflection causes troublesome use of buildings, underestimates their value, and in extreme situations leads to exceeded limit states. Therefore, such buildings are rectified by non-uniform elevations by means of jacks. On the basis of the analysed rectification processes, the method of determining the deflection of a building and the height of elevating its corners were presented depending on the type of building. This paper is a review of methods of determining the deflection of buildings having different sizes: single-storey buildings, single-storey buildings with a usable attic, two-storey buildings, and 11-storey buildings. Moreover, specific situations were analysed, in which the elevation height was determined by a range of additional works performed during rectification. This review was used to develop guidelines for determining deflection values and specifying the height of non-uniform elevation of corners.

Seismic performance of RC bent columns: Experimental, numerical and life-cycle cost analysis

Reinforced concrete (RC) bent structures are widely used in single-story industrial buildings, with a considerable portion of them located in high-intensity seismic areas. Therefore, it is significant to study the seismic performance of the RC bent column while keeping construction costs in mind. To evaluate the seismic performance of the RC bent column from an economic perspective, pseudo-static tests combined with construction cost analysis were first carried out on three RC bent columns designed according to different versions of Chinese codes. A numerical simulation method based on the extended finite element method (XFEM) for the RC bent column was then established and verified. Subsequently, the relationship between the local damage index related to the apparent damage characteristics and the overall damage index was established by conducting numerical analysis on RC bent columns with different design parameters. Based on the established relationship between the local and overall damage indexes, a calculation method for the residual bearing capacity based on apparent damage was developed. The results show that, when compared to the constructional requirements in the Chinese code for seismic design of industrial and civil buildings published in 1978 (TJ11–78), the constructional requirements in the Chinese code for seismic design of buildings published in 1989 (GBJ11–89) can effectively reduce the stress concentration at the column bottom and delay the formation of the plastic hinge with minimal cost increase, while the constructional requirements in the Chinese code for seismic design of buildings published in 2016 (GB50011–2010) can further effectively reduce the damage to the upper column. Besides, the constructional requirements in GBJ11–89 and GB50011–2010 can improve the energy dissipation and maximum bearing capacity of the RC bent column while decrease the cost/ductility coefficient by more than 5.0 %. The proposed calculation method can effectively predict the residual bearing capacity of earthquake-damaged RC bent columns by comparing the calculation results to the test results.