Jamal Nusairat

Probabilistic seismic hazard zonation of Syria

Earthquake hazard maps for Syria are presented in this paper. The Peak Ground Acceleration (PGA) and the Modified Mercalli Intensity (MMI) on bedrock, both with 90% probability of not being exceeded during a life time of 50, 100 and 200 years, respectively are developed. The probabilistic PGA and MMI values are evaluated assuming linear sources (faults) as potential sources of future earthquakes. A new attenuation relationship for this region is developed. Ten distinctive faults of potential earthquakes are identified in and around Syria. The pertinent parameters of each fault, such as theb-parameter in the Gutenberg-Richter formula, the annual rateλ4 and the upper bound magnitudem1 are determined from two sets of seismic data: the historical earthquakes and the instrumentally recorded earthquake data (AD 1900–1992). The seismic hazard maps developed are intended for preliminary analysis of new designs and seismic check of existing civil engineering structures.

p-y Curves for Rock and Intermediate Geomaterials Using Pressuremeter Tests

This paper presents proposed modifications to the existing methods that were originally developed to derive in-situ p-y curves from pressuremeter tests in soils to apply for pressuremeter tests in rock and/or intermediate geomaterials. The derived in-situ p-y curves can be used for the design of laterally loaded drilled shafts in rock and/or intermediate geomaterials. The proposed methodology was validated against two full-scale field lateral load tests conducted by the authors and five conducted by others from literature with rock pressuremeter or dilatometer tests performed at the test sites. The pressuremeter or dilatometer tests were performed in prebored holes cored using double tube core barrels. The modified methods for p-y curves of rock and intermediate geomaterials derived from pressuremeter interpretation would improve current design practice of laterally loaded drilled shafts socket in rock or intermediate geomaterials.

Design of Drilled Shafts Supporting Sound Walls

Abstract Drilled shafts are widely adopted as the foundation for sound walls. However, there has been a lack of uniformity in design and analysis methods and design criteria, in terms of factor of safety against ultimate capacity failure as well as the allowable deflection. In order to establish a uniform design methodology for the drilled shafts supporting sound walls in cohesive and cohesionless soils, respectively, a database of fullscale lateral load tests on fully instrumented drilled shafts was collected. Based on the compiled database, existing design methods and design criteria of laterally loaded drilled shafts were evaluated. Broms method and COM624P (or LPILE) are suggested as the design methods for drilled shafts supporting sound walls in both cohesive and cohesionless soils. Additionally, the corresponding design criteria, including factor of safety and permissible deflection, for both design methods are recommended. Two full-scale lateral load tests on fully instrumented drilled shafts were subsequently conducted in Colorado to further verify the design recommendation. A comprehensive geotechnical investigation program was also carried out at the two new lateral load test sites that included pressuremeter test, SPT, as well as laboratory triaxial consolidated undrained tests and direct shear tests on the soil samples taken from the lateral load test sites. The test results obtained at these two load test sites were employed to validate the recommended geotechnical design and geotechnical testing methods for the drilled shafts supporting sound walls.