Civil Engineering Department Grant MSC

Civil engineering department at University of Technology grnted MSC to the student Maryam Hussein for her thesis "Dynamic Loading Behavior of Pavement Layers on Sand Subgrade"

The thesis included the acquisition of reinforced paving layers that become popular in the field of civil engineering due to its flexible and versatile nature.

The augmented earth technology has taken a new turn in the time of using geosynthetics in civil engineering.

The research requirements are supplying material and manufacture of loading machine (loading tester). Materials include soil (sand), substrate, paving, layer, and plastic clamp. The testing program is providing 18 model such as layers under the flexible paving layer (bottom layer and base layers), model dimensions 1000*1000*800 mm, the bottom layer is 600mm thick and the base layer is 300 and 200mm.

The models were tested through the study to examine the vertical pressure distribution in the road layers due to the dynamic seismic load. Tests were performed to verify the effects of various parameters such as vibration frequency, loading behavior, core cycle thickness and plastic clamp location either between the core cycle and the substrate sand or at the center of the core. Vertical stress was recorded in the path layers for each frequency of 0.5, and 1.5HZ of unsupported and enforced models.

The sensors are evenly distributed to measure the vertical pressure at the layers and three laser displacements to measure horizontal and vertical displacement of the pavement layer.

The results showed that when the thickness of the substrate was 300mm, the addition of the plastic clamp stiffeners in the middle of the substrate and between the substrate and the sand layer of the substrate showed an increase in the transmitted stress by (14-49) % and a decrease in the maximum displacement by (35) % with an increase in the frequency from 0.5 to 1HZ. Also under the frequency of 1.5 HZ, the maximum pressure decrease but the horizontal displacement increase.

When the plastic clamp is placed between the base layer and the sand core layer with two thicknesses of the base layer 300 and 200mm, the pressure in the base layer and the asphalt layer by (12-17) %.

When the base thickness is 300mm, the best place for the plastic clamp is in the center of the layer, while for the base thickness is 200mm, the best place for the geo-grid is between the base layer and the sand layer.

The discussion committee was chaired by Prof.Dr.Hussein Hameed, and the membership of Asst.Prof.Dr.Mohameed Qader from University of Baghdad-Collage of Engineering, Lect.Dr.Ahmed Subhi from University of Technology- Civil engineering department. Prof.Dr.Yossif Fatah and Asst.prof.dr.Mayami Mohameed both are members and supervisors.