Performance-based Structural Design Research Articles

Performance-Based Design and Table Test Study on Hybrid Structure Combined with outside Steel Grid and Inner Reinforced Concrete Tube

With the hybrid structure including outer steel grids and inner reinforced concrete core tubes (RCCT) as the background, the key problems involved in the performance-based structural design are analyzed and the table test is conducted. Anti-seismic and stability indicators are defined based on the structural characteristics; The research on seismic response is made through elastic-plastic time-history analysis and verified through the table test; The overall stability of the outer steel grids and the anti-collapse capability following the ineffectiveness of some key components are analyzed. Results show that the structure in which the outer steel grids are connected with internal steel frame and RCCT is practicable, and the said three systems can work together effectively; The time-history analysis shows that the structure is weak at the elevation of 5-15m but can still meet the expected anti-seismic target under rare earthquakes. The space steel structure features sound stability and high redundancy, which ensures the structure will not collapse even if several key components are damaged.

Risk design optimization using many-objective evolutionary algorithm with application to performance-based wind engineering of tall buildings

Risk design optimization (RDO) is a competent approach for automated performance-based structural design by achieving a balance between safety and economy. Performance-based wind engineering (PBWE) is aimed at improving the life-cycle functionality of wind-sensitive structures, hence could be the very field RDO is tailor-made for. In this paper, we embed PBWE of tall buildings into RDO and tackle some difficulties when integrating them directly. We first formulate an integrated stiffness and vibration control RDO problem, and employ a frequency domain closed-form solution for uncertainty quantification and uncertainty propagation through the excitation–response–performance chain. Then we reveal the multi-objective optimization nature of RDO, and circumvent the difficulties in serviceability loss estimation by replacing scalar total cost with high-dimensional objective vector. Micro multi-objective particle swarm optimization in conjunction with kernel-learning based principle component analysis is employed to solve the corresponding many-objective problem with multiple probabilistic constraints and discrete design variables. The optimization results of CAARC benchmark indicate that we simplify risk-based PBWE of tall buildings from a complex multi-objective decision making process into a relatively easy multi-attribute decision making process. Accordingly, convincing decisions can be made based on the explicit building performance rather than the unreliable loss information.

Investigation on the Accuracy of Pushover Procedures for SDOF

The pushover analysis technique is mostly used in the performance-based design of structures and it is favored over nonlinear time-history analysis because of its lower computational cost. However, the accuracy of pushover is not well understood. With this problem in mind, the statistical relationship between the maximum displacement of nonlinear time-history analysis and that of pushover analysis is studied. It is indicated that the ratio of maximum displacement of nonlinear time-history analysis and that of pushover analysis follows lognormal probability distribution. For the structure with shorter period, the maximum displacement of pushover analysis is greater than the mean of maximum displacement of nonlinear time-history analysis; for the structure with longer period, the maximum displacement of pushover analysis tends to the same with the mean of maximum displacement of nonlinear time-history analysis. An expression for estimating the maximum displacement of structures under given peak ground acceleration with different excessive probabilities based on pushover result is proposed. Finally, an example is provided for demonstrating the application of the proposed expression.

Design for fire of concrete elements strengthened or reinforced with fibre-reinforced polymer: state of the art and opportunities from performance-based approaches

Recent years have seen widespread success applying fibre-reinforced polymer (FRP) materials for internal reinforcement and externally bonded strengthening of concrete structures. However, considerable reductions in mechanical and bond properties of FRP materials at elevated temperatures continue to hinder their application in buildings, where structural fire-resistance ratings are typically required. To meet currently imposed fire safety requirements, FRP materials often require supplemental fire protection insulation or thick concrete cover to maintain their temperature below an assumed (though not currently well-defined) “critical” value during an assumed standard fire exposure. Such requirements are based on a definition of structural fire resistance that is rooted in a prescriptive framework and that fails to take advantage of the state of the art in performance-based structural design for fire safety. This paper is intended to present a summary of the state of the art in this area and also to demonstrate clear opportunities for internal FRP reinforcement and external FRP strengthening of concrete elements that may arise from taking a performance-based fire safety design approach.

Probability-Based Research on Sensitivity of Saddle-Shaped Cables Suspended

Performance-based structural analysis is the main trend of the future development of engineering design; probability-based sensitivity can reflect the importance of different parameters in the structural performance-based design. Therefore based on the response surface method, the reliability analysis program has been established, within which the sensitivity analysis of different parameters, such as the prestress, cable sectional area, cable strength and elastic modulus of saddle-shaped cable suspended, was conducted. And the corresponding sensitivity coefficient has been given, which can not only be used as a reference to the design of structure, but also can check the rationality of the structure design.

Improved methodology for endurance time analysis: From time to seismic hazard return period

In the Endurance Time (ET) method, structures are subjected to a calibrated intensifying accelerogram and their performance is assessed based on their response at various equivalent intensity levels. Application of the ET method in performance-based design of structures has been studied by introducing a continuous performance target curve, which expresses the limit of the proper seismic performance of a structure along various times of the ET accelerogram. The correlation between time in the ET method and the return period for different structural periods is investigated. The procedure is based on the coincidence of response spectra obtained from the ET accelerogram at different times and response spectra defined by ASCE41 at different hazard levels. The results show that substitution of the return period for time in ET analysis and performance curves increases the usefulness of these curves and can simplify application of the ET method in performance-based design.

Structural Performance Assessment and Control of Super Tall Buildings During Construction

This paper addresses the structural performance assessment and control for super tall buildings during construction. Due to increasing structural complexity and economic investment of super tall buildings in recent years, the construction duration prolongs. Consequently, potential safety hazards may occur in structure when suffering from horizontal loads and vertical loads as well as non-loading effects in construction stage. The authors introduced performance based structural design (PBSD) methodology for the performance assessment and control of different structural states in different construction stages. The situation that the structural system will change along with the ongoing of construction procedure is considered. The critical issues with PBSD of super tall buildings during construction are fully addressed. By considering both gravity loads and lateral loads, the design criteria for construction stage structural systems were firstly discussed. A super tall building project was taken as an example in this paper to illustrate the proposed structural performance assessment during construction. It was shown that the proposed structural performance assessment method during construction phase is feasible and effective. It was also found that the arrangement of the lock-ins of outriggers for different construction stages is the key measure to control the performance of the mega frame outrigger corewall structures during construction.

Performance-Based Approach for the Design of a Deflection Hardened Hybrid Fiber-Reinforced Concrete

A numerical model that uses a nonlinear cracked hinge was developed to characterize the flexural behavior of a beam element composed of hybrid fiber-reinforced concrete (HyFRC). Deflection hardening performance criteria were established based on an average tensile strain capacity of 0.002 and a deterministic sensitivity analysis of the model. A HyFRC mix design is proposed that exceeds these performance criteria. The HyFRC flexural behavior and its flexural stiffness are compared against conventional reinforced concrete. Implications of the material flexural performance on performance-based structural design methods are discussed.

Assessment of modal pushover analysis and conventional nonlinear static procedure with load distributions of federal emergency management agency for high‐rise buildings

AbstractThe nonlinear static pushover analysis technique is mostly used in the performance‐based design of structures. However, the pushover analysis with load distributions of Federal Emergency Management Agency (FEMA) loses its accuracy in estimating the seismic responses of long‐period structures where higher mode effects are important. Recently, modal pushover analysis (MPA) has been proposed to consider these effects. Hence, FEMA load patterns and MPA are evaluated in the current study and compared with inelastic response history analysis. These approximate procedures are applied to medium‐rise (10 and 15 stories) and high‐rise (20 and 30 stories) buildings; advantages and limitations of them are elaborated. It is shown that MPA procedure presents significant advantage over FEMA load distributions in predicting story drifts. MPA is able to compute hinge plastic rotations better than FEMA load distributions at upper floor levels of high‐rise buildings due to considering higher mode effects by this procedure, but both are unsuccessful in predicting hinge plastic rotations with acceptable accuracy. Copyright © 2008 John Wiley & Sons, Ltd.

断層破壊のシナリオとその生起確率を考慮した地震ハザード解析に関する研究 : 断層モデルによる予測地震動を建物の性能設計法に実装するために

断層破壊のシナリオとその生起確率を考慮した地震ハザード解析に関する研究 : 断層モデルによる予測地震動を建物の性能設計法に実装するために

Damage Mechanics Modeling of Nonlinear Seismic Behavior of Concrete Structures

Performance-based design of structures is becoming the preferred seismic design method. Its use requires special numerical programs capable of predicting the performance of structures during a seismic event well into the nonlinear range. Seismic analysis results obtained from these programs depend on the types of elements and constitutive material laws used. For one type of element used, the results can be sensitive to the size of the elements. This paper presents a simplified finite-element analysis program based on multilayer elements and damage mechanics modeling of concrete behavior. A method to identify the various parameters required to define the behavior of the different materials is presented and some guidance on structural modeling using this type of program is provided. This program is used to predict the behavior of three different structures: overreinforced normal-strength concrete and high-strength concrete (HSC) beams tested monotonically, HSC columns tested under constant axial load and cyclic flexure, and bridge piers subjected to earthquake-type loading by the pseudodynamic test method. It is shown that predictions are in excellent agreement with experimental results.

Membrane action of slab/beam composite floor systems in fire

A structural performance-based design approach for steel beams supporting a composite floor system is presented allowing designers to specify fire protection to only a proportion of the steel beams within a given floor plate. The approach is a further development of a previous simplified design method where membrane action of the composite floor slab was included. The new method, presented in this paper, has been extended to incorporate the membrane action of the slab and beam system acting compositely, whereas the previous design method only considered the membrane action of the composite slab. In addition, the new method also includes the effect of the membrane action of the slab due to the variation in the deflected form, which is assumed to follow the changing yield-line patterns as the slab/beam system is heated in a fire. Previously, the membrane action of the composite slab was based on the lower-bound yield-line pattern assuming the slab and supporting beams acted independently. Comparison with the previous design approach shows that the simplifications, of ignoring the variation in the deflected form, and ignoring the contribution of the unprotected steel beams to the membrane load-carrying capacity of the system, were conservative.

Structural performance of scrap tire culverts

Culverts constructed of whole truck tires are a cost-effective alternative for draining water from small drainage basins with areas up to several hectares. Truck tire culvert design involves both hydraulic and structural performance considerations. This paper focuses on the structural considerations. Structural performance of truck tire culverts depends on the strength and stiffness of the truck tires and on their interaction with the surrounding backfill soil. The strength and stiffness properties of truck tires were determined by parallel plate testing. Field tests were conducted to evaluate the soil-structure interaction of buried truck tire culverts under a relatively shallow backfill. Responses with well-compacted and uncompacted (dumped) glacial till backfill soil were compared. Drawing on the results of the parallel plate tests and using the buried conduit test results for calibration, the Culvert Analysis and Design (CANDE) program was used to assess the load response of a truck tire culvert for a variety of backfill soils and to develop structural performance-based design guidelines.Key words: scrap tires, culvert, parallel plate test, field testing, CANDE.