Vibrations Due to Pile Driving

Vibrations due to pile installation have long been a concern to owners, contractors, and engineers. Specifically, what levels of vibrations can be assumed for a given pile, hammer, and subsurface conditions and how can these levels be predicted in advance of construction so an assessment of nearby structures can be made? This paper presents the results of vibration monitoring at several sites where various piles and pile hammers have been used, and recommends a conservative method of predicting peak particle velocity at the ground surface near pile installations. Where sensitive structures are involved, a response spectrum analysis is recommended

Variation in Capacities of Different Pile Types Under Similar Soil Conditions

The interaction between soil and various pile types is of interest because it depends not only on the shear strength characteristics of the soil, but also on the pile dimensions, shape, and installation method, and on time after pile installation. This paper presents load test results from three types of displacement piles installed at the same site. The results obtained from the tests are compared with theoretical estimates. The computed values of soil-pile adhesion, back-calculated from the load tests, are discussed and compared with values found in the literature. Estimated pile capacities during driving and retap are also compared and discussed

Differential Settlement of Nuclear Power Plant Foundations

A rational approach is presented for evaluating differential settlement of structures at nuclear power plants where settlement monitoring and the associated documentation are important. In nuclear plants, allowable differential settlement is governed by the necessity to prevent architectural and structural damage, equipment malfunction, touching of adjacent buildings during an earthquake, and damage to buried utilities. Measurements of actual settlement of the plant should be taken on a regular basis from start of construction and compared with the allowable values. A description is given of methods for calculating allowable values for differential settlements, and a comprehensive program for obtaining actual settlement data at a nuclear site is outlined. The ratio of measured to allowable differential settlement at which remedial action may be required is discussed. A case history of differential settlements at a nuclear plant is presented. The settlement patterns exhibited by the major structures can be correlated with foundation conditions at the plant site. Measured differential settlements are small, generally less than 0.25 inch, compared with values of allowable differential settlement which are mainly greater than 0.75 inch

Uplift Load Tests on Driven Piles

Details and results of uplift load tests on 25 piles at 15 sites are presented. The allowable uplift load on each pile determined from the BOCA code criterion is compared with an allowable capacity based on small movements at design load. In the majority of cases, the BOCA capacities are significantly lower

Accelerated Consolidation of Soft Clays Using Wick Drains

Construction of the New Istana for the Sultan of Brunei required that fill slopes up to 85 feet high be placed on very soft compressible floodplain soils. Wick drains installed in the soft sediments accelerated their consolidation and reduced long-term settlements. The consolidation also produced a strength increase in the soft soils that allowed the fill to be constructed without danger of a major base slip failure. Instrumentation installed in the floodplain soils provided data on excess porepressures built up during the fill placement, and on the resulting settlements. The measured porepressures and settlements were in good agreement with the predicted values

A heuristic algorithm for finding attractive fixed-length circuits in street maps

In this paper we consider the problem of determining fixed-length routes on a street map that start and end at the same location. We propose a heuristic for this problem based on finding pairs of edge-disjoint shortest paths, which can then be combined into a circuit. Various heuristics and filtering techniques are also proposed for improving the algorithm’s performance