Performance-based Building Design Research Articles

구획화재실험을 통한 온도 변화 예측 기법 연구

본 연구에서는 건축물에서의 성능기반 화재안전 설계 시에 사용되는 구획공간에서의 화재 성상 분석을 위해서 사무실 공간을 대상으로 하여 <TEX>$2.4(L){\times}3.6(W){\times}2.4(H)m$</TEX>의 크기의 구획 Mock-up을 제작하고 구획 내부에는 화재하중 <TEX>$18.74kg/m^2$</TEX>을 적용하여 책상, 의자, 컴퓨터 등과 같은 실제 가연물을 배치하여 화재실험을 실시하였다. 화재실험 결과, 구획 공간의 내부 중앙에서는 394~408 s 사이에 <TEX>$600^{\circ}C$</TEX>에 도달하였고 구획 입구 모서리에서는 404~420 s 사이에 <TEX>$600^{\circ}C$</TEX>에 도달하였다. 본 연구에서는 화재실험을 통해 측정된 온도변화 데이터를 BFD 곡선에 적용하여 화재시 구획 공간내의 온도변화 예측 기법을 분석하고자 하였으며, 화재실험을 통해 BFD 곡선 인자는 최대온도 <TEX>$900^{\circ}C$</TEX>, 최대온도 도달시간 7분과 형태계수 1.5로 결정하였다. BFD 곡선에 적용된 사무실 공간의 시간에 따른 온도 곡선은 화재초기에 빠르게 상승한 이후에 약 9분경 이후에 감소하는 형태를 나타내고 있다. In this study, the Mock-up office space experiments have been performed for the fire behavior analysis of the compartmented space used for the performance-based fire safety design of buildings. Mock-up test was conducted using the compartmented office space dimensions, which are 2.4 m wide, 3.6 m wide, and 2.4 m hight. Test was conducted with the combustible materials such as a desk, a chair, a computer ect. The fire load in the Mock-up office space was <TEX>$18.74kg/m^2$</TEX>. As a result, the temperature of the central compartment space to reach <TEX>$600^{\circ}C$</TEX> were 394 to 408 s. The temperature of the corner near the entrance edge to reach <TEX>$600^{\circ}C$</TEX> were 404 to 420 s. At this study, the temperature curve in the compartmented space has been predicted using the temperature data appling the BFD curve. The BFD curve factor based on the fire tests was determined by the maximum temperature of <TEX>$900^{\circ}C$</TEX>, 7 min to reach the maximum temperature, and the shape coefficient of 1.5. The initiating fire was rapidly increased to 9 min, and decreased.

프리스트레스트 콘크리트 보 부재의 잔류변형 산정에 대한 연구

Ulsan College, School of Environment & Building Design, Ulsan 682-715, KoreaABSTRACT To perform performance-based seismic design of buildings, it is necessary clear goal for usage and stability after an earthquake. To clear this goal, it requires a review of the constituent material of the building and, in particular, a member u sed as an indicator of the residual strain is useful. There are more usage of prestressed concrete because of prestressing steel witch has characteristics of the origin-oriented. In this study, the goal is estimating of residual strain on the prestressed concrete be am member. The expression for angle of deformed prestressed concrete beam member was obtained from using of curvature on the critical sect ion and the equivalent plastic hinge length based on ‘equivalent plastic hinge length method’. Considering the balance of strength and deformation conditions, suitable analysis values were derived from ‘split Element Method’. Through various parametric studies, various factors affecting the residual strain were decided. Based on the results of this study, it is expected many researches will be proceed in the future.Keywords : performance-based seismic design, stability, prestressed concrete, residual deformation, equivalent plastic hinge length

Agent-Based Fire Evacuation Model as a Tool for Fire Safety Design Assessment in Malaysia

Evacuation model is an important tool in formulating performance-based building design. It is a tool aims at helping designers assess the robustness of their design against factors such as human behaviour in fire. Currently, performance-based code for fire safety design has been the hot trend all over the world. Nevertheless, even though Malaysia is applying prescriptive-based code, performance-based approach for special buildings and mega projects are allowed. This shows that it is just a matter of time before performance-based code be fully adopted in place of prescriptive-based code in Malaysia. This paper aims to highlight how evacuation modelling may help designers assess the performance of their design. In this paper, an example of evacuation scenario was modelled and simulated using an agent-based fire evacuation model – FDS+Evac. The output of the simulation provide graphical representation such as the fire curve, the evacuation time, and the time to untenable condition that can be used to analyse the life safety objective based on concepts of ASET and RSET. The FED values of all occupants throughout the evacuation process are less than tenability criteria (0.3 FED). Therefore, it is concluded that all occupants have evacuated safely in the event of fire.

DIMENSIONADO PRELIMINAR BASADO EN RIGIDEZ DE EDIFICIOS ALTOS CON ESTRUCTURA DE ACERO RIGIDIZADOS CON DIAGONALES CONCÉNTRICAS

Se presenta una metodología para el dimensionado preliminar de un sistema resistente a sismos estructurado con base en marcos de acero rigidizados con diagonales concéntricas. La metodología aplica para el caso de edificios altos, cuya respuesta queda influida por componentes de deformación global en flexión y por el efecto de modos superiores de vibrar. Se presenta el dimensionado preliminar de los elementos estructurales de diferentes versiones de un sistema de contraventeo para un edificio de 24 pisos. A partir de la evaluación de las características dinámicas de las diferentes versiones del sistema de contraventeo, se concluye que la metodología propuesta conduce a un dimensionado adecuado durante el diseño preliminar basado en desempeño de edificios altos de acero contraventeados.

Modelling partial end-plate connections under fire conditions

This paper presents a simplified robust 2-noded connection element for modelling the behaviour of partial end-plate connections under fire conditions. In this new model the partial end-plate connection is modelled as a 2-noded nonlinear spring element. The characteristics of the spring – such as stiffness, tension, compression, shear strengths and bending moment resistance – are determined based on each component of the connection. It is well known that the rotational response of a partial end-plate connection comprises of two stages, due to the shift of the compression centre of the connection from the end of the endplate to the centre of the beam bottom flange at large rotation. This two stage behaviour is considered in the model proposed. Compared to normal component-based models the most significant of the current model is that this simplified model has very good numerical stability under static solver condition. The model also retains the advantages of both simple and component-based models. Fourteen tests of partial end-plate connection previously conducted by other researchers were used to validate the proposed model. It is evident that the model is capable to predict the behaviour of flexible end-plate connections under fire conditions. In order to investigate the influences of the connections on the behaviour of steel structures, a series of numerical studies has been conducted on a 2D steel frame, subjected to ISO834 Fire and Natural Fire. It is clear that the model can be used to represent the partial end-plate connections in performance-based fire resistance design of steel-framed composite buildings.

Automated generation of optimised building envelope: simulation based multi-objective process using evolutionary algorithm

This paper seeks to investigate methodology on the seamless integration for constructing a climate-conscious building envelope. The focus is targeted to provide architectural designers with an intelligent way to develop their design alternatives in the early phase of a project. Improved environmental performance can be achieved by using an optimised building envelope based on local data analysis. For tight integration, coupling of MATLAB and Rhino was employed through coding for real-time information exchanges. EnergyPlus and ECOTECT were implemented in the modelling process to simulate environmental performance. This process considers two cost functions: solar radiation and energy. Respective performance check-up runs into Multi-Objective Programming (MOP). Decision-making in MOP is optimised by using an Evolutionary Algorithm (EA), and culminated with Pareto efficiency. A sample experiment was conducted to test the methodology and results. The city, Moscow, having a conflicting claim of energy use reduction and increment of solar radiation due to its frigid local weather, was selected. Variants of adapted forms in the urban setting were visualised though the EA process in Rhino, and finalised to each dissimilar objective. The Pareto frontier method compromised the final models which were fitted best to energy and solar radiation each. The result shows how a form of building envelope can be adapted in a specific local context. This procedure serves to put forward a new user-oriented methodology and its application, intensifying the practical viability of performance-based building design in the future.

An Arbitrary Polynomial Chaos-Based Approach to Analyzing the Impacts of Design Parameters on Evacuation Time under Uncertainty

In performance-based design of buildings, much attention is paid to design parameters by fire engineers or experts. However, due to the time-consuming evacuation models, it is computationally prohibitive to adopt the conventional Monte Carlo simulation (MCS) to examine the effects of design parameters on evacuation time under uncertainty. To determine suitable design parameters under uncertainty with the reduced significantly computational cost, an arbitrary polynomial chaos-based method is presented in this paper. Arbitrary polynomial chaos expansion is used to construct surrogate models of evacuation time based on complex evacuation models. Afterwards, simple analytical method can be adapted to calculate the mean, standard deviation of evacuation time and Sobol sensitivity indices based on the arbitrary polynomial chaos coefficients. Moreover, the distribution of evacuation time can be generated by combining Latin hypercube sampling (LHS) with the obtained surrogate model. To demonstrate the proposed method, a hypothetical single-storey fire compartment with two exits is presented as a case in accordance with the Chinese code GB50016-2012, evaluating the impact of exit width on evacuation time under uncertain occupant density and child-occupant load ratio. And results show that the proposed method can achieve the distribution of evacuation time close to that from the MCS while dramatically reducing the number of evacuation simulations. When exit width per 100 persons is designed between 0.1 m and 0.5 m, the uncertainty of evacuation time is severely affected by exit width, which is more significant in smaller exit width. However, exit width has a small effect on Sobol sensitivity indices, the reliability level of a certain safety factor, and safety factor at a certain reliability level.

Numerical Simulation on the Character of Oil-pool-fire Plume

With the development of economy, the existing fire code can not adapt to the modern various special buildings, performance-based building fire protection analysis and design arises at the historic moment, FDS (Fire Dynamics Simulator) as the process of the development of the building fire simulation calculation of the main tool, also have been applied more and more. Based on the FDS, fire power per unit area with 57.5, 44.5, 33.0, 21.7, 14.4kW/m2 is chosen to simulate the open space fire using numerical simulation, and the result is compared to McCaffrey model. The results show that to a certain extent the simulation result of FDS with McCaffrey model has a certain similarity, but it appears a certain difference, even opposite result.

A model for pushover analysis of confined masonry structures: implementation and validation

Confined masonry (CM) is a typical building technique in Latin American countries. This technique, due to its simplicity of construction and similarity with traditional practices of reinforced concrete building, presents a potential of use in European regions with moderate-to-high seismicity. However, most of the procedures for seismic design in codes for Latin America are force-based, which appears to be inadequate due to the high dissipative response observed for CM. This paper presents a simplified numerical-analytical approach to model CM structures using pushover analysis, aiming to apply performance-based design procedures. First, a data mining process is performed on a database of experimental results collected from lateral tests on CM walls to adjust prediction models for the wall shear strength and to determine the input relevance through a sensitivity analysis. Then, an analytical model of CM structures for pushover analysis is proposed with basis on a wide-column approach that employs an adaptive shear load-displacement constitutive relation. The proposed method is compared with a discrete element model that represents explicitly the confinements-masonry interaction, against the experimental results obtained in a quasi-static test of a full-scale tridimensional CM structure. The accuracy of the predictions from both methods is very satisfactory, allowing to capture the base shear-displacement envelope and also the damage patterns of the structure, thus, demonstrating the ability of the methods to be used in performance-based seismic assessment and design of CM buildings.

Analysis of end-plate connections at elevated temperatures

In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between steel beam and column at elevated temperatures. The numerical procedure described is based on the model proposed by Huang (2011), incorporating additional developments to more precisely determinate the tension, compression and bending moment capacities of end-plate connection in fire. The proper failure criteria are proposed to calculate the tension capacity for each individual bolt row. In this new model the connection failure due to bending, axial tension, compression and shear are considered. The influence of the axial force of the connected beam on the connection is also taken into account. This new model has the advantages of both the simple and component-based models. In order to validate the model a total of 22 tests are used. It is evident that this new connection model has ability to accurately predict the behaviour of the end-plate connection at elevated temperatures, and can be used to represent the end-plate connections in supporting performance-based fire resistance design of steel-framed composite buildings.

Development of a solid reaction kinetics gypsum dehydration model appropriate for CFD simulation of gypsum plasterboard wall assemblies exposed to fire

Gypsum plasterboard wall assemblies are extensively used as cladding material for walls, floors and ceilings, as well as a means for passive fire protection of timber structures. The good fire resistance characteristics of gypsum plasterboards are mainly owed to the gypsum “dehydration” process, occurring between 80°C and 250°C, where large quantities of energy are absorbed by evaporating water molecules, bound in the gypsum's crystal lattice. Aiming to enhance the prediction quality of numerical simulation tools, utilized to support the performance-based fire design of modern buildings, a gypsum dehydration numerical model is developed and validated. The model focuses on accurately describing the physical and chemical phenomena characterizing the gypsum dehydration process by employing a modelling approach based on solid reaction kinetics; temperature-dependent thermo-physical properties are also taken into account. The developed model is implemented in a Computational Fluid Dynamics code. Numerical results are validated by comparison to available temperature measurements obtained in a gypsum plasterboard wall assembly tested in a small-scale fire resistance furnace. Predictions of the developed model are found to agree reasonably well with the experimental data; a series of parametric studies is also performed aiming to investigate the effect of various modelling parameters.

Evaluation of Modal Pushover–Based Scaling of One Component of Ground Motion: Tall Buildings

Nonlinear response history analysis (RHA) is now increasingly used for performance-based seismic design of tall buildings. Required for nonlinear RHAs is a set of ground motions selected and scaled appropriately so that analysis results would be accurate (unbiased) and efficient (having relatively small dispersion). This paper evaluates accuracy and efficiency of recently developed modal pushover– based scaling (MPS) method to scale ground motions for tall buildings. The procedure presented explicitly considers structural strength and is based on the standard intensity measure (IM) of spectral acceleration in a form convenient for evaluating existing structures or proposed designs for new structures. Based on results presented for two actual buildings (19 and 52 stories, respectively), it is demonstrated that the MPS procedure provided a highly accurate estimate of the engineering demand parameters (EDPs), accompanied by significantly reduced record-to-record variability of the responses. In addition, the MPS procedure is shown to be superior to the scaling procedure specified in the ASCE/SEI 7-05 document.

Mitigation of Progressive Collapse in Multi-Storey Buildings

This paper describes recent developments in performance-based design of multi-storey buildings against progressive collapse, where particular emphasis is given to practical implementation within the structural design process. The benefits of sudden column loss as an event-independent scenario are highlighted, and its computational merits as well as its correlation with actual extreme dynamic events are emphasised. It is proposed that the robustness limit state should be based on avoidance of failure in the upper floors above the damaged column, where it is proposed that the design envelope should be stretched from the conventional strength limit to the ductility limit so as to achieve economic design for robustness. In addressing the dynamic effects of sudden column loss, load factor approaches that have been recently proposed for use with some new usa design codes are shown to have serious shortcomings, potentially leading to unsafe estimation of dynamic amplification. These shortcomings are effectively addressed by the ductility-centred approach recently developed at imperial college london, which offers a practical multi-level assessment framework for progressive collapse under sudden column loss. Key lessons are drawn from the application of the ductility-centred approach to steel-concrete composite multi-storey buildings, where the inadequacy of prescriptive and load factor approaches is clearly demonstrated, and where the benefits of such factors as connection ductility, additional connection reinforcement, axial restraint, infill panels and rate-sensitivity are highlighted.

Performance-based seismic analysis and design of code-exceeding tall buildings in Mainland China

Design codes provide the minimum requirements for the design of code-compliant structures to ensure the safety of the life and property. As for code-exceeding buildings, the requirements for design are not sufficient and the approval of such structures is vague. In mainland China in recent years, a large number of code-exceeding tall buildings, whether their heights exceed the limit for the respective structure type or the extent of irregularity is violated, have been constructed. Performance-based seismic design (PBSD) approach has been highly recommended and become necessary to demonstrate the performance of code-exceeding tall buildings at least equivalent to code intent of safety. This paper proposes the general methodologies of performance-based seismic analysis and design of code-exceeding tall buildings in Mainland China. The PBSD approach proposed here includes selection of performance objectives, determination of design philosophy, establishment of design criteria for structural components and systems consistent with the desirable and transparent performance objectives, and seismic performance analysis and evaluation through extensive numerical analysis or further experimental study if necessary. The seismic analysis and design of 101-story Shanghai World Financial Center Tower is introduced as a typical engineering example where the PBSD approach is followed. The example demonstrates that the PBSD approach is an appropriate way to control efficiently the seismic damage on the structure and ensure the predictable and safe performance.

Influences of exit and stair conditions on human evacuation in a dormitory

Evacuation processes of students are investigated by experiment and simulation. The experiment is performed for students evacuating from a dormitory with an exit and stairs. FDS+Evac is proposed to simulate the exit and stair dynamics of occupant evacuation. Concerning the exit and stair widths, we put forward some useful standpoints. Good agreement is achieved between the predicted results and experimental results. With the increase of exit width, a significant stratification phenomenon will be found in flow rate. Stratification phenomenon is that two different stable flow rates will emerge during the evacuation. And the flow rate curve looks like a ladder. The larger the exit width, the earlier the stratification phenomenon appears. When exit width is more than 2.0 m, the flow rate of each exit width is divided into two stable stages, and the evacuation times show almost no change. The judgment that the existence of stairs causes flow stratification is reasonable. By changing the width of the stairs, we proved that judgment. The smaller the width of BC, the earlier the stratification appears. We found that scenario 5 is the most adverse circumstance. Those results are helpful in performance-based design of buildings.

A Monte Carlo analysis of the effect of heat release rate uncertainty on available safe egress time

Available safe egress time is an important criterion to determine occupant safety in performance-based fire protection design of buildings. There are many factors affecting the calculation of available safe egress time, such as heat release rate, smoke toxicity and the geometry of the building. Heat release rate is the most critical factor. Due to the variation of fuel layout, initial ignition location and many other factors, significant uncertainties are associated with heat release rate. Traditionally, fire safety engineers prefer to ignore these uncertainties, and a fixed value of heat release rate is assigned based on experience. This makes the available safe egress time results subjective. To quantify the effect of uncertainties in heat release rate on available safe egress time, a Monte Carlo simulation approach is implemented for a case study of a single hypothetical fire compartment in a commercial building. First, the effect of deterministic peak heat release rate and fire growth rate on the predicted available safe egress time is studied. Then, the effect of uncertainties in peak heat release rate and fire growth rate are analyzed separately. Normal and log-normal distributions are employed to characterize peak heat release rate and fire growth rate, respectively. Finally, the effect of uncertainties in both peak heat release rate and fire growth rate on available safe egress time are analyzed. Illustrations are also provided on how to utilize probabilistic functions, such as the cumulative density function and complementary cumulative distribution function, to help fire safety engineers develop proper design fires. (Less)

Performance-Based Seismic Design of Midrise Woodframe Buildings

The understanding of, and ability to predict, the seismic behavior of woodframe structures has improved immensely in the last 10 years. Two notable projects occurred in succession, the Consortium of Universities for Research in Earthquake Engineering (CUREE) and California Institute of Technology (Caltech) CUREE-Caltech Woodframe Project, and the Network for Earthquake Engineering Simulation (NEES) NEESWood Project, which provided greater understanding, improved analytical modeling, and advances in force- and performance-based seismic design (PBSD) of woodframe buildings, respectively. The NEESWood project focused on the development of a PBSD philosophy (and procedures) for midrise woodframe buildings and included full-scale system-level validation. To date, the complete design procedure has not been systematically explained, which serves as the impetus for this paper. While the method was shown to be quite viable, some challenges remain, including identifying a format that would facilitate widespread adoption and use by engineers. Thus, this paper examines the progress, current state, and challenges for PBSD of midrise woodframe buildings.

Optimal performance-based design of wind sensitive tall buildings considering uncertainties

Two major wind-induced performance indexes of tall buildings excited by dynamic and random wind could be the lateral drift and acceleration. The wind-induced performance-based design optimization framework has been developed to take into account uncertainties in the vibration related occupant comfort problems of tall buildings. An innovative decoupling strategy is adopted to transform the original coupled reliability-based optimization problem into two separated sub problems, which are then solved using the inverse reliability approach and Optimality Criteria (OC) algorithm respectively. A 60-story building example is employed to demonstrate the effectiveness and practicality of the proposed reliability performance-based design optimization method.

Probabilistic procedure for wood-frame roof sheathing panel debris impact to windows in hurricanes

The assessment of losses during extreme events such as hurricanes is important for performance-based design of residential buildings. In this paper, a methodology for estimating the probability of debris impact, specifically roof sheathing panels, to windows as a result of hurricanes is introduced and applied to a series of illustrative examples. The methodology is a combination of approaches on flat plate trajectories, numerical hurricane modeling, and statistical analysis of structural capacity. Within this methodology, one can estimate the probability of impact for one or more windows in a certain house group as a hurricane approaches and passes on a deterministic track as defined by the center of its eye. The impact probability is analyzed for each hour making up the full hurricane duration rather than a single analysis using the blended (total) hurricane statistics. An illustration of the method is presented through an assessment of windborne debris impacts to windows in a house group located near the US Gulf coast using a hurricane having the same track as hurricane Katrina in 2005. As a result, the probability of each window being hit by a roof sheathing panel (RSP) during each hour of the hurricane as well as during each of the example hurricanes is presented. The results quantify the probability from hour to hour during a hurricane and will provide a more accurate estimate of the probability and timing of pressurization of buildings for total loss estimation including rainwater intrusion volumes.

Performance-based Fire Protection Design of Domestic Super High-rise Buildings - Evaluation by ASET and RSET -

초고층 빌딩 건설 시 요구되는 성능위주 소방설계는 인명 안전을 확보할 수 있는 능동적인 대책으로서 화재 위험성을 평가하고, 공학적 분석 결과를 토대로 하여 방재시스템을 구축하는 것으로 관련 법규 및 기준을 적용하여 수행하는 기존의 설계 방식보다 인명 안전의 확보에 있어서 매우 효율적이고 타당하다고 보여진다. 본 연구는 피난 요구 시간인 RSET과 피난이 가능한 시간인 ASET에 의한Time-line Analysis을 적용하였으며 또한 ASET과 RSET을 비교, 분석하기 위하여 화재 및 피난 시뮬레이션을 수행하였다. 연구 결과, 스프링클러설비가ASET을 증가시켰으며, 화재감지 및 경보시간의 단축이 RSET을 효과적으로 감소시켜 주고 있다. 단축된 시간은 인명의 안전을 확보하는데 많은 영향을 미치는 것으로 확인되었다. 또한 소화설비, 화재 감지 및 경보설비가 정상적으로 작동되도록 유지 관리되는 것도 중요한 것으로 파악되었다. 화재의 성상을 데이터 베이스화하고 피난 대응 프로그램 등이 구축되면 성능위주 설계에 유용한 자료로 이용될 수 있다. The Performance-based fire protection design required to construct super high-rise building is the active measure for the evaluation of fire risks and the establishment of fire protection systems on the basis of engineering analysis, which is more efficient and proper than existing prescriptive-based design. This study applied time-line analysis of RSET is required safe egress time and ASET is available safe egress time with the fire and evacuation simulation to analyze. The result of this study showed the sprinkler system increased ASET and fire detection and alarm system reduced RSET efficiently. Reduced evacuation time influences to secure the life safety. Also it is essential to maintain the fire suppression system and fire detection & alarm system properly. Database of fire movement and evacuation action program are useful for the performance-based design.