An experimental investigation of retrofitted cripple walls

1991 ◽  
Vol 81 (5) ◽  
pp. 2111-2126
Author(s):  
R. Shepherd ◽  
E. O. Delos-Santos
Keyword(s):  
Experimental Investigation ◽  
Full Scale ◽  
Contributory Factor ◽  
Cyclic Loads ◽  
Loma Prieta Earthquake ◽  
Damping Characteristics ◽  
Frame Buildings ◽  
Loma Prieta ◽  
Wood Frame ◽  
Extensive Damage

Abstract Extensive damage was experienced by wood-frame buildings during the Loma Prieta earthquake. A significant contributory factor was the collapse of cripple walls. This prompted the examination of the behavior of a group of full-scale retrofitted cripple walls subjected to in-plane cyclic loads. The results of investigating seven cripple walls, each 2 ft (0.61 m) high and 16 ft (5 m) long, are presented. Two are control panels, without retrofits. Two are strengthened with 1 by 6 inch (25.4 by 153 mm) braces. Two are retrofitted with 0.5 inch (12.7 mm) plywood and one with a steel strap tie. Stiffness, strength, and damping characteristics are summarized, together with cost aspects. It is shown that relatively cheap and straightforward modifications can substantially eliminate the vulnerability of many existing cripple walls to earthquake shaking.

Full-Scale Experimental Verification of Soft-Story-Only Retrofits of Wood-Frame Buildings using Hybrid Testing

2014 ◽  
Vol 19 (3) ◽  
pp. 410-430 ◽  
Author(s):  
Elaina Jennings ◽  
John W. van de Lindt ◽  
Ershad Ziaei ◽  
Pouria Bahmani ◽  
Sangki Park ◽  
...  
Keyword(s):  
Experimental Verification ◽  
Full Scale ◽  
Hybrid Testing ◽  
Soft Story ◽  
Frame Buildings ◽  
Wood Frame

Evaluation of a Loss Estimation Procedure Based on Data from the Loma Prieta Earthquake

1995 ◽  
Vol 11 (1) ◽  
pp. 37-61 ◽  
Author(s):  
Nicholas P. Jones ◽  
Sólveig Thorvaldsdóttir ◽  
Anqi Liu ◽  
Prakash Narayan ◽  
Thomas Warthen
Keyword(s):  
Structural Damage ◽  
Estimation Procedure ◽  
Loss Estimation ◽  
Estimation Model ◽  
Loma Prieta Earthquake ◽  
Loss Data ◽  
Basic Parameters ◽  
Loma Prieta ◽  
Wood Frame ◽  
The City

Over the several past decades, methods have been developed to predict structural damage on a regional basis. This paper describes an effort to collect damage and loss data from the Loma Prieta Earthquake and the comparison of these data with the results calculated by an existing loss estimation model. First the intensity prediction was evaluated by comparing the model results with the Modified Mercalli Intensity (MMI) maps issued by the U.S. Geological Survey in areas affected by the Loma Prieta earthquake. Then, the study concentrated on losses of the City of Watsonville in the County of Santa Cruz. The sensitivity of the loss due to variation in some of the basic parameters, such as intensity, deductible and liquefaction potential, were studied and discussed. The damage distribution of wood-frame buildings was also investigated. Results of calculations were compared with the collected real loss data (on-site estimate and permit estimate) from the City of Watsonville. The comparison shows that while the extant model offers some insight into loss distributions, more research is clearly necessary to improve the physical underpinnings of the methodology and to provide the necessary statistical data on which these approaches are based.

scholarly journals Effect of Loading Speed on the Mechanical Properties of Nail Joints

2019 ◽  
pp. 462-470
Author(s):  
Shervin Shameli Derakshan ◽  
Lina Zhou ◽  
Chun Ni
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Shear Walls ◽  
Experimental Tests ◽  
Cyclic Loads ◽  
Test Results ◽  
Cyclic Tests ◽  
Frame Buildings ◽  
Wood Frame ◽  
Reversed Cyclic

Wood shear walls are the main lateral load resisting systems in light wood frame buildings to resist the wind and seismic loads. Sheathing to lumber nail connections are regarded as the key components that control the resistance and failure modes of wood shear walls. Considerable experimental tests have been conducted on performance of nail joints or wood shear walls under both static and reversed cyclic loads. However, these tests were usually conducted under different loading speed causing specimen failure in 1 min to an hour. It is unclear how the loading speed will affect the test results of nail joints or wood shear walls. Research on these topics is limited. This paper aims to evaluate the effect of loading speed on the mechanical characteristics of nail joints. 72 specimens have been tested under various loading speeds, ranging from 0.05 mm/s to 0.5 mm/s for monotonic tests and 1.5 mm/s to 15 mm/s for reversed cyclic tests. The range of loading speed was selected based on the total estimated loading time that both monotonic and reversed cyclic tests fail within around 1 min to 10 min. Two groups of nail joints, comprising two common nail sizes and two sheathing thicknesses, were assessed under both monotonic and reversed cyclic loads. From the test results, the effect of loading speed on the mechanical properties of nail joints was determined.

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