Spelling suggestions: "subject:"standoff distance"" "subject:"standoffs distance""
1 |
Influence of Nozzle Pressure, Standoff Distance, and Reinforcing Steel Cage on Water Jetting of CIDH Pile AnomaliesSchaffer, Matthew Jason 01 March 2011 (has links)
The effectiveness of removing anomalous material from cast-in-drilled-hole (CIDH) piles by water jetting was examined. The primary objectives of this research were to examine how reinforcing steel influences water jetting and to evaluate how jetting pressures and standoff distance from the material surface affect water jetting of concrete type materials and PVC tubing. The experimental work consisted of water blasting submerged test specimens using rotary jets, nozzles, pumping equipment, and testing procedures currently used in construction practice. The concrete test specimens were comprised of ring- and cylinder-shaped samples, containing materials with compressive strengths of approximately 160 and 3,600 psi. Typical PVC tubing used as inspection access holes for non-destructive testing in CIDH piles was utilized for tubing specimens. During testing, erosion depths were measured as a function of standoff distance and jetting pressure. Water jetted specimens containing reinforcing steel were cut apart after testing to permit inspection of the erosion cavity and eroded material surfaces behind the steel reinforcement. Reinforcing steel bars in CIDH piles do interfere with the jet path and will locally influence material erosion and water-jetting effectiveness. For a relatively weak material, water-jetting pressures between 10,000 and 11,000 psi produced erosion up to a radial distance of approximately 12 inches from the water jet. This erosion distance is less than half the typical maximum design spacing of PVC inspection access tubing installed in CIDH piles.
|
2 |
Performance and Design of Retention Anchors in Blast Resistant WindowsAlameer, Alameer Marai 01 December 2020 (has links)
Windows in building façade are vulnerable to blast pressures. When subjected to blast shock waves, glass windows may suffer failures, potentially causing serious injuries and casualties to the building occupants due to the flying glass shards and other projectiles. Protective films and laminated glass are widely used to protect windows against blast loads. These techniques have proven to reduce or prevent hazards associated with glass breakage. The use of steel or strengthened aluminum frames also reduce window blast hazards associated with frame failures. However, such measures are not always sufficient to mitigate the blast hazard if window retention anchors do not have sufficient resistance to blast pressures. Research on blast resistant windows is scarce in the literature. Therefore, a comprehensive research project was undertaken to address the behaviour, analysis, and design of window retention anchors. The research program consisted of combined experimental and analytical components. Three main phases were pursued, comprising of: i) Experimental research using a shock tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) of analysis, and iii) Non-linear dynamic analysis of window systems based on a single-degree-of-freedom (SDOF) simplification.
The experimental phase consisted of tests of 23 punched windows mounted on four different types of substrates consisting of structural steel, reinforced concrete, concrete block masonry, and stone masonry. The experimental parameters included window size and aspect ratio, glazing type, protective film thickness, substrate type, as well as the number and pattern of window retention anchors. Two levels of blast pressure-impulse combinations were used as per the recommendations of the U.S General Services Administration (GSA).The numerical phase involved FEM modelling and analysis of selected test windows. The FEM models were first validated against test results. The validated models were then employed to conduct an analytical parametric study. The parameters in this phase consisted of; substrate type, window frame rigidity, anchor fixity level in the substrate, window aspect ratio and size, anchor spacing, and blast pressure-impulse combination. The results demonstrated the significance of design parameters on window response, while also defining anchor force distribution along the window frame.
A simplified SDOF method of analysis was developed for window systems, including the effects of anchor flexibility and substrate rigidity on non-linear response. The analysis approach includes the construction of window resistance functions in pre-break and post-break phases of response, where the latter stage of response is dominated by the membrane action of protective film. The analysis leads to the computation of anchor design forces, which have been validated against anchor shear and axial tension forces recorded experimentally. The SDOF analysis is recommended for use in designing blast-resistant window retention anchors on different substrates.
|
3 |
Sportcentrum Broumov / Sports center in BroumovVolf, Josef January 2014 (has links)
The topic of the masters thesis is newly built sports center in Broumov on the outskirts of the historic center. The proposal was placed high demands on appearance. There is a non-traditional stone facade with a combination of wood ventilated facades. The combination of wood and stone construction gives a historic feel and fit and existing buildings, which will carry the dominant built-up area. The new building is set into the sloping terrain with a flair for existing buildings. The building is part sunk into the ground to reduce the height to the surrounding area. The sports center is divided into three dilatations objects: Technical facilities, sports hall, bowling with squash and gym.
|
Page generated in 0.4598 seconds