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04/04/2020


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Data Resources Category
Data Resources Category A refereed Conference
Research Title ASSESSMENT OF SEISMIC SITE EFFECT FOR RAWABI FIRST PALESTINIAN PLANNED CITY

Published by (sources)

First International Conference on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE 16-19 May 2012, Bacau, Romania

Carried out by (authors)

Jalal Al Dabbeek
Issue Year 2012
Abstract

The aim of the study is to avoid or mitigate seismic site effect, such as: landslides, amplification and faulting systems. Seismic refraction technique was used to investigate the city of Rawabi Site. More than 30 seismic profiles have been shot to figure out the subsurface geology and to delineate if there are cavities beneath the selected landfill site. The underground seismic models beneath the profiles show different velocities to two or three layers; the first layer represents the soil cover (weathered surface material) with maximum thickness of about 5 m overlaying a layer of sediment material (marly and clay- marly materials) or directly on consolidated carbonate materials of limestone, chalky limestone, and dolomite limestone. The underground seismic models and the time-distance results don't show clear cavities at shallow depths except slight morphological variations at bottom of marly layer which may indicate small voids. The shear wave velocity values (Vs) vary between 500 m/sec and 1500 m/sec for marly materials and hard limestone respectively. Based on thicknesses of layers and the values of Vs for each layer, the type of soil profile at the foundation levels varies between SB and SC.

 

The effects of local geology on ground-motion amplification and building damage were studied in Rawabi City (first stage – phase 1). Nakamura’s method of microtremor analysis was applied in this investigation. The measurements showed large differences in amplification between few selected sites. Calculating the natural period of the proposed common buildings (Tb) in the studied, the values obtained were closed to the site dominant natural period (Ts) in few locations. On the other hand, reducing the marly stratum level in city center area by 10 – 20 meters as proposed in the master plan, will have a positive effect on reducing the seismic amplification factor measured at city center area. In the other areas (Sector 1 to 6), the amplification factor is relatively small.

 

To avoid landslides phenomenas, several slope stability analysis sections have been done in the proposed site of Rawabi City. The study models all expected cases such as excavation, building loads, backfill materials behind retaining walls and embankments and expected seismic loads. Analysis was carried out for given sections through Sector 1 and for virtual sections according to topography and local geology through the rest of the sites. Results show that the stability of slopes within the site is safe. However, it is recommended to construct the buildings on the hard limestone bedrock layer and using backfill materials according to standards. 

 

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