Showing papers by "John W. van de Lindt published in 2011"

Damage Study and Future Direction for Structural Design Following the Tuscaloosa Tornado of 2011

Abstract: David O. Prevatt, Ph.D., P.E., University of Florida, Gainesville, FL John W. van de Lindt, Ph.D., University of Alabama, Tuscaloosa, AL Andrew Graettinger, Ph.D., University of Alabama, Tuscaloosa, AL William Coulbourne, P.E., Applied Technology Council, Rehoboth Beach, DE Rakesh Gupta, Ph.D., Oregon State University, Corvallis, OR Shiling Pei, Ph.D., P.E., South Dakota State University, Brookings, SD Samuel Hensen, P.E., Simpson Strong Tie, Pleasanton, CA David Grau, Ph.D., University of Alabama, Tuscaloosa, AL

Modeling System Effects and Structural Load Paths in a Wood-Framed Structure

Abstract: The objective of this project was to evaluate system effects and further define load paths within a light-frame wood structure under extreme wind events. The three-dimensional 30- by 40-ft (9.1- by 12.2-m) building, designed to be representative of typical light-frame wood construction in the southeastern coastal region of the United States, was modeled using SAP2000. Wall and roof sheathing was modeled using SAP’s built-in thick shell element. The effect of edge nail spacing of the wall sheathing was incorporated by way of a novel correlation procedure, which eliminated the need to represent each nail individually. The computer model was validated against both two- and three-dimensional experimental studies (in plane and out of plane). Uniform uplift pressure, worst-case simulated hurricane, and ASCE 7-05 pressures were applied to the roof, and vertical foundation reactions were evaluated. The ASCE 7-05 uplift pressures were found to adequately encompass the range of uplift reactions that can be expected...

Seismic Performance and Modeling of a Half-Scale Base-Isolated Wood Frame Building

Abstract: The concept of base isolation is a century old, but application to civil engineering structures has only occurred over the last several decades. Application to light-frame wood buildings in North America has been virtually non existent with one notable exception. This article quantitatively examines issues associated with application of base isolation in light-frame wood building systems including: (1) constructability issues related to ensuring sufficient in-plane floor diaphragm stiffness to transfer shear from the superstructure to the isolation system; (2) evaluation of experimental seismic performance of a half-scale base-isolated light-frame wood building; and (3) development of a displacement–based seismic design method and numerical model and their comparison with experimental results. The results of the study demonstrate that friction pendulum system (FPS) bearings offer a technically viable passive seismic protection system for light-frame wood buildings in high seismic zones. Specifically, the ...

IDA Comparison of IBC-Designed and DDD-Designed Six-Story Light-Frame Wood Buildings

Abstract: The current International Building Code (IBC) allows wood-frame (i.e., light-frame wood) construction to be three stories high or four stories high if sprinklers are included in the design. Several jurisdictions within the United States have opted to allow four and five stories if sprinklers are present. This paper presents a comprehensive numerical analysis of a six-story wood-frame building designed on the basis of the 2006 IBC methodology and a building designed by using the direct-displacement design (DDD) approach. The objectives of the design methods are different and are explained herein. Incremental dynamic analysis (IDA) was used to numerically investigate the response of the buildings on the basis of two criteria: the peak interstory drift and the building’s base shear capacity. Gypsum wall board was included in both models, but exterior finishes (e.g., stucco) were not.

Prescriptive Approach to the Performance-Based Seismic Design of Low-Rise Wood-Frame Residential Buildings

Abstract: Performance-based seismic design (PBSD) is considered by many to be the next generation of design philosophy that focuses on the system performance of a structure during earthquake loading. For steel and concrete structures, this design philosophy is being used by a select group of practitioners. However, application to wood-frame buildings is still in the research stages; several approaches for PBSD are proposed with rehabilitation concepts available in ASCE 41. Currently, most of the PBSD methods for wood-frame buildings require designers to utilize a level of approach that is far more detailed than current design approaches. This increases the cost of any engineering for the design of wood-frame buildings. Therefore, in this study, a simplified design approach is developed that allows a designer to employ the PBSD methodology without complex analysis. Different from most existing PBSD procedures, this prescriptive approach was developed based on a significant number of numerical simulations using a sim...

Approach for Establishing Approximate Load Carrying Capacity for Bridges with Unknown Material and Unknown Design Properties

Abstract: There are 16 small to medium simple span bridges in Larimer County that are currently load rated solely based on visual inspections. Most of these bridges are prestressed concrete bridges. The objective of this project is to load rate these bridges using structural analysis with very little to no information available related to their design. Larimer County provided everything available, which essentially was very limited plans and inspection reports for the bridges. The plans lacked details concerning prestress, cross-section dimensions, and material properties. The bridge (prestress concrete) manufacturer does not have records of the bridges built in the 1960’s or earlier. Due to these limitations, a basic structural analysis was performed using a program developed for the Colorado Department of Transportation (CDOT) in 2007 with rating-conservative assumptions in order to determine the capacities of the bridges. The influence of these assumptions on the conclusions is also discussed.

Cementitious Spray Dryer Ash-Tire Fiber Material for Maximizing Waste Diversion

Abstract: Spray dryer absorber (SDA) material, also known as spray dryer ash, is a byproduct of coal combustion and flue gas scrubbing processes that has self-cementing properties similar to those of class C fly ash. SDA material does not usually meet the existing standards for use as a pozzolan in Portland cement concrete due to its characteristically high sulfur content, and thus unlike fly ash, it is rarely put to beneficial use. This paper presents the results of a study with the objective of developing beneficial uses for SDA material in building materials when combined with tire fiber reinforcement originating from a recycling process. Specifically, spray dryer ash was investigated for use as the primary or even the sole binding component in a mortar or concrete. This study differs from previous research in that it focuses on very high contents of spray dryer ash (80 to 100 percent) in a hardened product. The overarching objective is to divert products that are normally sent to landfills and provide benefit to society in beneficial applications.

Seismic Performance Comparison of a High-Content SDA Frame and Standard RC Frame

Abstract: This study presents the method and results of an experiment to study the seismic behavior of a concrete portal frame with fifty percent of its cement content replaced with a spray dryer ash (SDA). Based on multiple-shake-table tests, the high content SDA frame was found to perform as well as the standard concrete frame for two earthquakes exceeding design-level intensity earthquakes. Hence, from a purely seismic/structural standpoint, it may be possible to replace approximately fifty percent of cement in a concrete mix with SDA for the construction of structural members in high seismic zones. This would help significantly redirect spray dryer ash away from landfills, thus, providing a sustainable greener alternative to concrete that uses only Portland cement, or only a small percentage of SDA or fly ash.