Master of Science / Department of Architectural Engineering and Construction Science / Kimberly W. Kramer / Soils conditions vary throughout the United States and effect the behavior of the foundation system for building structures. The structural engineer needs to design a foundation system for a superstructure that is compatible with the soil conditions present at the site. Foundation systems can be classified as shallow and deep, and behave differently with different soils. Shallow foundation systems are typically used on sites with stiff soils, such as compacted sands or firm silts. Deep foundation systems are typically used on sites with soft soils, such as loose sands and expansive clays. A parametric study is performed within this report analyzing tilt-up concrete structures in Dallas, Texas, Denver, Colorado, and Kansas City, Missouri to determine the most economical tilt-up wall panel and foundation support system. These three locations represent a broad region within the Midwest of low-seismic activity, enabling the use of Ordinary Precast Wall Panels for the lateral force resisting system. Tilt-up wall panels are slender load-bearing walls constructed of reinforced concrete, cast on site, and lifted into their final position. Both a 32 ft (9.75 m) and 40 ft (12 m) tilt-up wall panel height are designed on three foundation systems: spread footings, continuous footings, and drilled piers. These two wall heights are typical for single-story or two-story structures and industrial warehouse projects. Spread footings and continuous footings are shallow foundation systems and drilled piers are a deep foundation system. Dallas and Denver both have vast presence of expansive soils while Kansas City has more abundant stiff soils. The analysis procedure used for the design of the tilt-up wall panels is the Alternative Design of Slender Walls in the American Concrete Institute standard ACI 318-05 Building Code and Commentary Section 14.8. Tilt-up wall panel design is typically controlled by lateral instability as a result from lateral loads combining with the axial loads to produce secondary moments. The provisions in the Alternative Design of Slender Walls consider progressive collapse of the wall panel from the increased deflection resulting from the secondary moments. Each tilt-up wall panel type studied is designed in each of the three locations on each foundation system type and the most economical section is recommended.

<p>The research contained in this thesis is concerned with longterm behaviour of drilled piers socketed in weak rock. The experimental work involved testing of two steel and seven concrete model piers. The 25.4 mm (1.0 in) diameter steel piers had relatively smooth socket walls (RF = 0.033) and were socketed into pseudo-rock material. The concrete piers were 76.2 mm (3.0 in) in diameter and were socketed into weak rock (Queenston Shale). The concrete piers were of two types: conventional socketed piers with relatively smooth socket walls (RF = 0.025) and grooved piers with relatively rough socket walls (RF = 0.081 and 0.303).</p> <p>The piers were tested under two condition of load support, shaft resistance only and combined shaft resistance and end-bearing support conditions.</p> <p>In case of steel piers, electrical resistance strain gauges were mounted on the pier shaft to measure the load distribution along the shaft of the piers. For concrete piers under combined shaft resistance and end-bearing support conditions, flat jack load cells with Marsh and Budenberg pressure gauges and/or electrical pressure transducers were used to measure the load transfer at the base.</p> <p>All model piers were axially loaded in the laboratory using load frames designed and fabricated for this purpose. The axial loads were iii applied by the air cylinders and held constant throughout the period of testing using a regulated air pressure supply.</p> <p>The test results confirmed that performance of socketed piers can be significantly improved by increasing the roughness of the pier-rock interface. Both the primary creep rate and the load transfer with time were larger for piers with small shaft roughness.</p> <p>A second stage of creep having a much lower creep rate was observed for all model tests. The time to the end of primary creep was found to depend on the roughness of the socket wall. The primary and secondary creep rate appeared to be dependent on the stress level, shaft roughness, compressive strength of weak rock and support conditions.</p> <p>The results of the model tests are compared with available test data and with values predicted using methods based on viscoelastic analysis. This method of analysis for piles in clay soils has been modified for application to socket piers in weak rock. It is suggested that the modifications can be used to estimate the long-term settlement of socket piers in weak rock</p> / Master of Engineering (ME)