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The large-scale and catastrophic impacts of Hurricanes Katrina and Rita in 2005 challenged the efficacy of traditional postdisaster temporary housing methods. To address these challenges, the U.S. Congress appropriated $400 million to the Department of Homeland Security to support alternative housing pilot programs, which encourage innovative housing solutions that will facilitate sustainable and permanent affordable housing in addition to serving as temporary housing. Facilitating and maximizing the sustainability of postdisaster alternative housing is an important objective that has significant social, economic, and environmental impacts. This paper presents the development of a novel optimization model that is capable of (1) evaluating the sustainability of integrated housing recovery efforts under the alternative housing pilot program and (2) identifying the housing projects that maximize sustainability. An application example is analyzed to demonstrate the use of the developed model and its unique capabilities in maximizing the sustainability of integrated housing recovery efforts after natural disasters. DOI: 10.1061/(ASCE)CO. 1943-7862.0000185 CE Database subject headings: Optimization; Housing; Hurricanes; Disaster recovery; United States. Author keywords: Optimization; Postdisaster alternative housing; Sustainability; Housing Recovery.

Due to the nonlinear nature of coordinate transformations, evaluation and calibration of multiaxial loading systems in global Cartesian coordinates are challenging problems. This study proposes a systematic calibration method for multiaxial loading systems in global coordinates using an external measurement system. Global coordinate measurement for a multiaxial loading system is usually obtained from a geometric transformation based on internal actuator measurements. However, any misrepresentation of initial actuator configuration (e.g., origin, pin locations, etc.) introduces errors and cross-talk in the global Cartesian coordinates. Such errors and cross-talk cannot be observed or eliminated based on internal measurements. The method proposed in this paper is based on the sensitivity of the global coordinates with respect to the initial actuator length. To validate the proposed method, calibration is performed using the state-of-the-art Load and Boundary Condition Box at University of Illinois at Urbana-Champaign as the multiaxial loading system and the Krypton Dynamic Measurement Machine as the external measurement system. Experimental results demonstrate that the proposed sensitivity-based external calibration method is effective for improving control accuracy and reducing cross-talk of multiaxial loading systems in global Cartesian coordinates. DOI: 10.1061/(ASCE)0733-9399(2010)136:2(189) CE Database subject headings: Sensitivity analysis; Calibration; Transformation.

A multiplatform simulation of a highway overcrossing bridge is introduced where the embankments, abutments, and pile groups are modeled in a powerful finite-element (FE) package with nonlinear soil material model while the bridge is modeled in another FE package that excels in fiber-based frame analysis. The Meloland Road Overcrossing Bridge, which is heavily instrumented, is selected as a reference analysis model due to the existence of measured data. The components as well as the integrated system are verified through comparison with previous studies and measured data. The stiffness of abutments and pile foundations are evaluated by three-dimensional finite-element analysis and compared with those from previous investigations. The analytical models of abutments and foundations are combined with the structural model using the multiplatform analysis framework, UI-SimCor. The dynamic properties of the model for multiplatform analysis are compared with those evaluated from system identification techniques using recorded ground motion. Finally, response history analyses are conducted with recorded free-field ground motion. The analysis results are in very good agreement with measured response showing the promising potential of multiplatform dynamic simulation. DOI: 10.1061/(ASCE)0733-9445(2008)134:4(651) CE Database subject headings: Seismic analysis; Roads; Simulation; Computer software; Bridges, highway.

Motivated by the observation that existing damage indices do not take into account the bidirectional and torsional response effects, a new three dimensional damage index is proposed in this paper. The derivation is based on decomposing the 3D structure into planar frames. A local damage index that is sensitive to out-of-plane responses is described and a method to combine local damage indices is presented. The proposed index is verified by comparison with conventional damage indices. DOI: 10.1061/(ASCE)0733-9445(2006) 132:9(1482) CE Database subject headings: Damage assessment; Earthquake engineering; Biaxial loads; Torsion.

Recent analytical studies have shown that reduced column compression and even tension may be experienced by intermediate stories of medium to high-rise reinforced concrete (RC) structures. This is a consequence of high overturning moments coexisting with vertical ground motion. In recognition of such observations, the present study was initiated to investigate the seismic performance of interior beam-column subassemblages under reduced column compression or net tension. A state-of-the-art synchronized shake-table facility was used to test a total of six ordinary and marginal high-strength RC interior subassemblages. A nonconventional design approach was adopted to ensure pure panel-zone (PZ) shear failure, hence a realistic estimate of joint shear strength will ensue. Results indicated loss of shear capacity and increase in deformability when compression column load is markedly reduced or tension is experienced. Findings of this investigation are most useful in providing necessary information about the effect of axial tension on the PZ shear capacity, the joint confinement efficiency, and the overall structural stability in areas of potential high vertical earthquake excitations.

In this paper, modeling approaches describing the hysteretic behavior of reinforced-concrete columns subjected to cyclic deformation reversals are investigated. The inelastic flexure and shear response of a reinforced-concrete column subjected to cyclic deformation is evaluated utilizing lumped hysteretic representations that exhibit efficiency and ease of modeling. The analytical predictions obtained with the new formulations are compared with experimental results from the literature. Comparisons between results with and without shear interaction reveal the importance of the flexure-shear interrelationship and the adequacy of the proposed approach in terms of strength and stiffness predictions.

Analytical methods are frequently utilized for structural assessment due to their simplicity and cost-effectiveness. However, modeling of material inelasticity and geometric nonlinearity under reversed inelastic deformations is still very challenging and its accuracy is difficult to quantify. On the other hand, realistic experimental assessment is costly, time-consuming, and impractical for large or spatially extended structures. Hybrid simulation has been developed as an approach that combines the realism of experimental techniques with the economy of analytical tools. In hybrid simulation, the structural is divided into several modules such that the critical components are tested in the laboratory, while the rest of the structure is simulated numerically. The equations of motion solved in the computer enable the integration of the analytical and experimental components at each time increment. The objective of this article is to apply a newly developed identification and model updating scheme to acquire the material constitutive relationship from the physically tested specimen during the analysis to two complex hybrid simulation case studies. The identification scheme is developed and verified in a companion article, while the two experiments presented in this article are selected such that they address different structural engineering applications. First, a beam-column steel connection with heat treated beam section is analyzed. Afterwards, the response of a multi-bay concrete bridge is investigated. The results of these two examples demonstrate the effectiveness of model updating to improve the numerical model response as compared to the conventional hybrid simulation approaches. [ABSTRACT FROM PUBLISHER]

Hybrid simulation has been effectively utilized to assess structural response subjected to intense dynamic loads. The process comprises dividing the structure into experimental and numerical modules. The experimental modules represent the critical components responses, which cannot be idealized reliably through analytical approaches. The responses of the different modules are combined through a stepwise integration scheme. In conventional hybrid simulations, the number of experimental components is restricted by the capacity of the test facility; usually 1–3 components, and the numerical simulation does not benefit from the information acquired from the tested component during the analysis. In this article, a framework is proposed to identify the material constitutive relationship from the tested component(s) and to update the corresponding numerical parts that share close characteristics with the physical tests. Optimization tools and neural networks are presented as alternatives for the identification procedure; the framework is however extendable and scalable. The communication protocol between the different structural components is also discussed within the proposed framework. Several analytical examples are presented to prove the feasibility of the presented framework, while experiments are used to verify the process in a companion article. [ABSTRACT FROM PUBLISHER]