The development of cross-laminated timber (CLT) panel technology has opened up new opportunities for wood in tall buildings. Several characteristics including seismic performance and speed of construction have raised interest among designers. As CLT gains acceptance in the industry, alternative structural solutions need to be investigated to improve performance of...
One of the recent additions to the panoply of engineered wood products is cross-laminated timber (CLT). CLT is a prefabricated, large-scale, solid wood panel that consists of multiple layers of lumbers stacked together, with each layer arranged perpendicular to the next layer, glued with structural grade adhesives, and pressed. The...
Current bridge design codes do not account for the effects of duration of mega-thrust subduction zone earthquakes. Furthermore, codes and even recent performance-based design methodologies only make use of the peak response quantities (forces, displacements, and ductility demands) and do not account for the increased number of inelastic cycles that...
Connections in mass timber structural systems dissipate energy and transfer lateral forces from mass timber elements such as shear walls and diaphragms, providing critical load paths. Cross-laminated timber (CLT) is a prominent mass timber material used to manufacture wall and floor assemblies. Fire performance research of CLT walls and floors...
The role of ground motion duration on the seismic performance of civil engineering structures remains unclear. Thus, the role of earthquake strong ground motion duration is assessed in a three manuscript thesis, which includes: (1) assessment of the effects of ground motion duration on the seismic performance of a model...
In this thesis, the effectiveness of the 100 percent + XX percent seismic response directional combination rule available in codes and standards is evaluated using simulated nonlinear seismic response of two existing multi-story reinforced concrete plan-irregular buildings. The 5-story and 8-story buildings were designed according to the 1975 seismic codes...
For mid-rise and high rise buildings, slender reinforced concrete (RC) structural walls are commonly used as the main structural elements to resist lateral applied loads in high seismically areas around the globe. These RC structural walls can provide substantial deformation capacity, stiffness, and lateral strength through the contribution of their...
Use of high-strength steel (HSS) reinforcing bars could provide constructability and economic benefits for the construction of structures, reducing the initial and ultimately the life-cycle cost of bridge and building structural elements. This thesis summarizes work performed in a research project on the use of HSS reinforcing bars for concrete...
Cross-laminated timber (CLT) panels have been gaining popularity as diaphragm elements in mid- to high-rise construction projects. In addition, CLT-concrete composite (CCC) diaphragms have been implemented to expand the use of CLT diaphragms. To understand the behavior of CLT and CCC diaphragms, this research effort sought to characterize the cyclic,...
The overarching objective of this study is to examine and compare the vulnerabilities of bridges combining effects of earthquake-induced ground shaking, ground failure (e.g., landslides and lateral spreading), and tsunami inundation. A parametric study is performed to understand the sensitivity of economic loss and traffic capacity with respect to the...
During the 2011 Great East Japan Earthquake and Tsunami, numerous bridge structures were damage or destroyed. The damage to bridge systems was caused by long duration strong ground shaking, tsunami inundation forces, or both. Long duration strong ground shaking from subduction zone earthquakes and the multi-hazard scenario of combined earthquake...
Cross-Laminated Timber (CLT) is one of the latest engineered wood products to show promising structural features for a variety of structural purposes including resisting lateral loads. For CLT to be widely adopted, its modal behavior needs to be fully evaluated through experimental and numerical methods. It is important to the...
This project determines the short term and long term effective stiffness values for Cross Laminated Timber (CLT) with a reinforced concrete topping. The reinforced concrete was attached to the CLT panels with interface connections, and different types of interface connections were tested. Throughout this project, there are 31 tests with...
The use of high strength steel reinforcement has the potential to provide economic and constructability benefits when used in reinforced concrete structures. However, more research is needed to justify and confidently allow its use. Current design provisions limit the nominal yield strength of reinforcing steel bars to 60 ksi (420...
Wood plays a key role in modern electrical infrastructure; crossarms and power poles utilize the high strength to weight ratio, availability and low cost of wood to facilitate the access of power to millions of Americans. However, wood presents a variety of challenges as a material. In structural applications, one...
Tsunamis have the potential to inflict severe damage and loss of life in coastal communities. Structures known as vertical evacuation buildings provide an alternative evacuation site for communities living in relatively flat, coastal regions with inadequate sources of high ground for evacuation. Design of these structures balances risk and economy,...
Concrete formwork is a common type of temporary structure used on construction projects. Due to difficulties in considering actual construction site implications during formwork design, assessments of formwork integrity are often made in the field by site personnel based on subjective visual inspection. The use and re-use of concrete formwork...
A significant number of Unreinforced Masonry (URM) buildings exist in the Pacific Northwest region of the United States of America that is a region of high seismicity, which could be subjected to both crustal and subduction zone earthquakes. The catastrophic and brittle failures associated with URM buildings in the past...
The steel diagrid structural system is a recent load bearing and lateral resisting structural system for tall building structures that is relatively unexplored in the western United States. One possible reason for the little use of diagrid systems in earthquake prone regions is the lack of guidelines and application examples...
The research presented in this thesis assessed the use of high strength steel (HSS) reinforcement for use in reinforced concrete (RC) bridge columns. HSS is not currently allowed in reinforced concrete bridge columns due to a lack of information on the material characteristics and performance information when used in RC...
Large numbers of reinforced concrete (RC) bridges were built in the past that are now considered seismically deficient. The structural members most likely to be considered deficient are the supporting columns. Typical deficient columns contain inadequate transverse reinforcement and poorly detailed lap splice lengths above the foundation. Insufficient lap splice...
There are many aging bridges in service in the US and around the world that were not constructed to modern seismic design codes and standards. As a result, they are expected to perform poorly during intense earthquake ground shaking. Older reinforced concrete (RC) bridges, in particular, are often supported on...
Earthquake engineering analyses are often performed using shallow, crustal earthquake motions (e.g., 1940 El Centro). However, large areas of the world are subject to subduction zone earthquake motions (e.g., the Pacific Northwest). A subduction zone earthquake motion is characterized by its long duration (e.g., strong shaking lasts for more than...
Cross-laminated timber (CLT) is an attractive building material because it is renewable, promotes fast installation, and possesses a high strength-to-weight ratio. The use of CLT in seismic applications has become increasingly common with the development of post-tensioned CLT rocking wall lateral force resisting systems (LFRS). The CLT pier-and-spandrel system designed,...