|CUREE-Caltech Woodframe Project
Element 1 - Testing & Analysis
Project Manager: André Filiatrault - University at Buffalo, SUNY (formerly at UCSD)
The Testing and Analysis element will, for the first time, conduct investigations into woodframe seismic behavior on a sufficient scale, and with the necessary coordination with organizations in the fields of professional practice (e.g. SEAOC and SEAOSC), codes (e.g. , ICBO), and research (e.g., Forest Products Laboratory and universities) to allow reliable woodframe designs to be implemented and intended performance achieved, for retrofit as well as new construction. There is a strong consensus among both structural engineers and researchers that individual "pieces" or components, such as shear wall panels, when combined to form a real wood building, do not really behave the way current building code woodframe provisions assume.
Furthermore, even when a qualified engineer uses state of the art engineering for designing a wood building, the current consensus is that reliability is still not achieved: Some components or connections end up too strong or too weak, or more ductile or less than expected, and under strong shaking unexpected damage occurs where it should have been avoided. In the case of all three other basic materials--concrete, steel, masonry--an extensively rationalized and testing-based design philosophy has already been codified that specifically targets which components of the building should "give" first--how the beams should yield before columns, where to avoid using too much reinforcing as well as too little, what kind of cracking in a shear wall should occur, etc.
And while life-threatening collapse is relatively unusual with woodframe construction, the damage cost may be surprisingly expensive. Documentation of the need for large-scale physical testing of woodframe components and entire building assemblages is given later. In parallel with the planned testing, analytical studies using the testing data will generate the quantitative understanding of actual behavior necessary to produce effective engineering, code, and construction changes.
|Task 1.1.1 - Shake Table Tests of a Simplified Two-Story Single-Family House
The main objective is to perform shake table testing on a simplified full-scale two-story single-family house to measure and quantify the building's overall dynamic responses for various construction configurations and to document how the distribution of forces within the structure may change between the various configurations.
|Task 1.1.2 - Shake Table Test of Multi-Story Apartment Building with Tuck-under Parking
The main objective is to conduct multi-directional shake table tests of a full-scale three-story multi-family building with tuck-under parking. The building is designed and constructed to represent 1960s engineering practice in Northern California. In addition to testing the original building, a rehabilitated building will be tested using a special moment resisting steel frame in the open front to improve the seismic performance of the first story.
|Task 1.1.3 - Shake Table Tests Simplified Model
This research program is conducted at the University of British Columbia under a project entitled "Reliability and design of innovative wood structures under earthquake and extreme wind conditions" funded by Forest Renewal BC Research Program.
|Task 1.2 - Organization of an International Benchmark
The main objective of Task 1.2 is to organize an International Benchmark based on one particular shake table testing phase of Task 1.1.1 of the CUREE-Caltech Woodframe Project.
|Task 1.3.1 - Loading Protocol and Rate of Loading Effects
Static and dynamic tests on woodframed shearwalls performed with the objective of a comparison of results given by the use of different protocols and loading rates.
|Task 1.3.2 - Development of Testing Protocols
The objective is to establish common testing protocols for all component tests and shake table tests for the Woodframe Project.
|Task 1.3.3 - Dynamic Characteristics of Wood-Frame Buildings
To determine the dynamic characteristics (natural frequencies and damping) of woodframe structures and to develop a period formula specific for wood structures by regressing on appropriate structural characteristics.
|Task 220.127.116.11 - Anchorage of Woodframe Buildings
The main objective is to improve the understanding of the cyclic behavior of sill plate-to-foundation anchorage connections for a wide range of anchorage configurations. Another objective is to develop sill plate connections that do not exhibit brittle type failures.
|Task 18.104.22.168 - Anchorage Hillside Buildings to Foundation Tests
The main objectives of the project are to improve the understanding of the behavior of diaphragm-to-foundation connections that are typical in hillside constructions, and to verify the efficiency of retrofit measures as recommended in the Los Angeles City Hillside Woodframe Buildings Retrofit Ordinance and to provide background data to guide the design practice.
|Task 1.4.2 - Design Methodology for Diaphragms
This project is developing information on the performance of wood diaphragms. The project is primarily an experimental study intended to quantify the stiffness of wood diaphragms that are in two conditions (nailed sheathing, and glued and nailed sheathing.)
|Task 1.4.3 - Seismic Behavior of Constant Height and Stepped Cripple Walls
The objective of this project is to characterize the in-plane seismic behavior of cripple walls, and is intended to contribute towards the performance-based design of woodframe structures. Design values for the lateral strength and ductility capacity of cripple walls will be characterized through full-scale experimental testing. Evolution and distribution of damage within the wall, which are important for performance assessment, will be identified at various stages of testing.
|Task 1.4.4 - Behavior of Shear Walls
The main objective of this task is to complement the CoLA shear wall project,provide a comparison to the behavior of the UCSD two-story houses shear walls, evaluate the hysteretic behavior designed to current code requirements, evaluate the effects of perforations, composite behavior, and aspect ratio.
|Task 1.4.6 - Wall Finish Materials
The overall aim of the investigation is to understand the damage characteristics and to accurately relate seismic response to wall repair costs. A related component of the study is to improve understanding of the shear strength and stiffness gypsum drywalls and to develop response models that can be incorporated in simulation studies to look at the performance of overall woodframe systems.
This task includes investigations of seismic response and damage to gypsum drywall.
|Task 1.4.7 - Innovative Systems
The main objective of this research project is to investigate the suitability of fluid dampers for seismic protection of light-framed wood buildings.
|Task 22.214.171.124 - Nail and Screw Fastener Connections
The objective of the research is to establish a database for sheathing-to-wood connections from which parameters necessary for modeling purposes can be extracted.
|Task 126.96.36.199 - Inter-Story Shear Transfer in Woodframe Buildings
The research conducted in Task 188.8.131.52 will experimentally evaluate the inter-story shear transfer mechanism in wood-frame buildings.
|Task 184.108.40.206 - Connection Studies
Connection tests were conducted at UC Irvine in 1995 to determine the performance of several diaphragm-to-shear wall connections. These tests showed that significant deformation occurs within the region between the top plates of a wall and the floor or roof diaphragm. Furthermore, the deformation can be quite different depending on the orientation of the floor or roof joists.
|Task 1.5.1 - Development of a Seismic Analysis Software for Woodframe Construction
The main objective of Task 1.5.1 is to develop a specialized computer platform for the nonlinear seismic analysis of woodframe buildings.
|Task 1.5.2 - Demand Aspects
The main objective of Task 1.5.2 is to provide information on the seismic demands (deformations and forces) on the main components of the lateral-load resisting systems of woodframe construction. This information is to be used to evaluate the adequacy of current code procedures and to provide the background for a rational performance-based seismic design procedure.
|Task 1.5.3 - Reliability Studies
Task 1.5.3 has the following specific objectives: (i) modeling uncertainty analysis, (ii) response variability analysis, and (iii) suggest one possible reliability-based approach to shearwall design/selection.