Deep Basement Construction Through an Existing Basemement at the Central Business District of Hong Kong

In June 2002, a 32-storey high quality commercial building with a 3-level deep basement, namely Chater House, was completed. The Chater House site was previously occupied by the Swire House and its basement structure and foundations obstructed the construction of the new basement. Temporary pipe pile walls with grout curtain were used to facilitate local trimming/demolition of the existing basement slab and pile caps. Diaphragm walls were constructed through the locally demolished basement to retain the soils for the 15m deep excavation and the new basement was constructed by top-down construction method. In addition, the diaphragm walls and large diameter bored piles were constructed to support the vertical loads and wind shear from the superstructure. This paper describes the geotechnical design aspects of the new development. The difficulties and special issues during the substructure construction works are also discussed. Instrumentation monitoring results are also reviewed and compared with the predicted movements

Strategic Interaction and Spatial Multiplier Effects in Local Growth Control Policies: The California Housing Market

Since the 1970s, growth controls spread across many metropolitan regions in the United States. Several studies address the effects of local growth controls on housing markets, particularly its price effect, which is induced by rising construction cost, constrained housing supply, improved amenities, and market reorientation of homebuilders. However, only few studies explicitly address inter-jurisdictional spatial spillovers and strategic interaction of policy-makers of different jurisdictions in the design of growth control policies. This study focuses on two housing market outcomes, supply of new housing and market orientation, and utilizes a spatial econometric framework to systematically investigate local and global spatial spillovers giving rise to spatial multiplier effects. Preliminary results suggest that market orientation of new home building is primarily influenced by population growth and building permit caps, with positive spillovers at the local level only. For the supply of new housing, however, the models seem to suggest positive global spillover effects. However, there is additional indication of a potential relevance of including spatial heterogeneity in the model specification. Specifically, a north-south disparity or a coastal-inland disparity may have non-negligible impacts with concurrent implications for policy-making.spatial spillovers, growth controls, housing supply, market orientation, Public Economics, C21, H23, H73, R31,

The Classic, Summer 2015

Zwemer View: A Whole Education for Your Whole Life; Around the Green: Green is Great; Doing Missions Well; In Box; Second National Ranking; Caps & Gowns; More Learning Opportunities; On Sabbatical; Campus Life: Summer Jobs; Interim Provost; The Science of Great Teaching; New Admissions Leaders; Construction Update; Servant Professor; Cleaning Service; Prestigious Scholarship; Endowed Professor Appointment; Face Value: Ann Vander Kooi Minnick; A Job Well Done: Good Sport, Academic Leader, Grandma Raider, Campus Carpenter; Red Zone; Master Teachers; 1000 Words: A Dutch Welkom; A New Look at Campus; Tiny House Big Ideas; Bullets to Beauty; Wheel Love; Made to Create; Of Minor Prophets; Teacher of the Year; Red Ties; Class Notes; New Arrivals; Marriages; In Memoriam; Classic Thoughts: Ripple Effect; Summer Internhttps://nwcommons.nwciowa.edu/classic2010/1015/thumbnail.jp

Improving Construction Processes by Integrating Lean, Green, and Six-Sigma

The overall goal of this research was to develop and implement methods to improve the performance and the efficiency of construction processes prior to and during the construction phase in Design-Bid-Build (DBB) projects. In order to accomplish these goals, the three methods Lean, Green, and Six-Sigma were implemented in two different scenarios and validated by different case studies. First, a framework was developed that integrated the three methods Lean, Green, and Six-Sigma with an overall layout of the Define, Measure, Analyze, Improve, and Control (DMAIC) improvement model. The framework was then validated via a construction process of installation of pile caps for an educational institute during the construction phase in Pittsburgh. The framework highlighted two issues with the pile caps construction process. First, disparate quantities of materials (purchased and installed) were determined. Second, the pile caps construction process took a total time of 54 business days while it could have been completed in 30 business days. Using life cycle assessment, environmental impacts of the pile cap construction process were analyzed and results showed that major environmental impacts including global warming potential, release of carcinogenics, negative respiratory effects, ozone depletion, and ecotoxcity could result from the materials used for the process. Next, the root causes behind waste generation were determined via developing and administrating a questionnaire to a local construction company. Second, the previously developed framework was further validated and applied to a residential development project in Saudi Arabia. The construction sector has been growing rapidly in Saudi Arabia; however, the quality of Saudi Arabian construction is decreasing, resulting in excess waste generation and associated environmental impacts. This case study examined a project with 53 residential units overall but only 10 units acceptable at final inspection. The largest quality issue was determined to be exterior paint blistering. Using the developed framework, defective units were investigated through a field examination, narrowing down the causes of the blistering applying the Pareto method as follows: Inadequate method, untrained workers, weather, and others. Next, the Process improvement tool was applied to reduce the blistering causes and to improve the current process. A new method designed and applied to a separate residential unit for validation. The modified method showed a great improvement and in the end the unit was able to pass inspection. Finally, building on the previous case studies, the framework was later refined with the goal of applying it earlier in a project, prior to construction, to further reduce potential waste generation and associated environmental impacts. Using Lean Green, and Six-Sigma (LG6) and adopting the same improvement model, DMAIC, the owner can evaluate all steps separately in the process, addressing all resources consumed and analyzing environmental impacts which might be generated; this highlights potential waste and so can help the owner avoid waste occurrence by indicating where the process needs to be amended to create less environmental impact and more efficiency. For this research, the model was used to help evaluate the construction process for the installation of 160 woodpiles. The model identified that four steps out of eight were considered as non-adding value steps or waste. Three steps out of four non-adding value steps were involved with moving down, moving around, and setting up the equipment. The remaining wasteful step was cutting to length all installed woodpiles. The model showed that if these steps were replaced, eliminated or planned well, environmental impacts would be reduced by 9% and expenses by 1%

Subexponential groups in 4-manifold topology

We present a new, more elementary proof of the Freedman-Teichner result that the geometric classification techniques (surgery, s-cobordism, and pseudoisotopy) hold for topological 4-manifolds with groups of subexponential growth. In an appendix Freedman and Teichner give a correction to their original proof, and reformulate the growth estimates in terms of coarse geometry.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol4/paper14.abs.htm