Concrete pile

Consider the explosion of a propane-air vapor cloud confined beneath a storage tank. The tank is supported 1 m off the ground by concrete piles. The concentration of vapor in the cloud is assumed to be at stoichiometric concentrations. Assume a cloud volume of 2094 m3, confined below the tank, representing the volume underneath the tank. Determine the overpressure from this vapor cloud explosion at a distance of 100 m from the blast using the TNO multi-energy method. 

Precast concrete piles will be used with an allowable compression force of 80 kips (356 kN) and an allowable tension force of 50 kips (222 kN), both with a safely factor of 3 against ultimate capacity. Because battered piles will resist all lateral forces without the need for passive soil pressure, a safety factor of 1.2 may be used. Permissible blast capacities will be adjusted accordingly. 

The effect produced by the incorporation of a lignosulfonate-based water-reducing agent is shown in Table 7.6. The results were obtained from a series of mixes over an 8-month period by a ready-mix plant used in the production of concrete piles. Since the standard deviation of this particular plant was 5.0 MPa for mixes produced without the use of admixtures, it is evident that the use of the admixture resulted in reduced variability. These results indicate that in high workability mixes with cement contents in the median range, the admixture may cause an increase in the standard deviation. Thus in redesigning the mix to have a lower cement content in this class of concrete, adequate consideration should be given to this difference in standard deviation. Increased uniformity can be attained in this instance... 

The actual load carrying capacity of a sand pile is much less than that of a similar size concrete pile. The surest way to determine capacity is by field load tests. 

Figure 10.2 Stabilization of sand to prevent foundation movement. (Courtesy of Raymond Concrete Pile Division, NY.)...

Composite piling. For economy a combination of wood and concrete piling is used for deep bed work. The wood section is driven below the elevation of the lowest ground-water elevation to avoid decay, and then the upper section is poured concrete in a metal shell. 

The cost of CP systems varies depending on the type of system used. In this regard, Virginia DOT has published a report entitled, Evaluation of Anodes for Galvanic Cathodic Prevention of Steel Corrosion in the Prestressed Concrete Piles in Marine Environments in Virginia (30). The data in this report and the data in the literature published by Virmani (2) suggest that the sprayed Al-Zn-In alloy or the zinc-hydrogel systems with a life of 10-20 years cost 108-129/m. ... 

Rapa, M. and Hartt, W.H. (Apr, 1999). Non-Destructive Evaluation of Jacketed Prestressed Concrete Piles For Corrosion Damage. NACE Corrosion 99. Paper No. 566. 

Table 5.1 summarizes the structural strengths of precast concrete piles, adopted from the Malaysian Standard (MS 1314 1993). Table 5.2 lists the basic structural requirements for precast concrete piles. 

Table 5.1. Structural strengths of precast concrete piles (MS 1314 1993).

Type class of pile requirements Precast reinforced concrete pile Precast pretensioned concrete pile Precast pretensioned spun concrete pile ... 

A pile helmet (Figure 5.20) is required to distribute the blow from the hammer evenly to the head of the pile, to cushion the blow and to protect the pile itself. A dolly is placed in a recess in the helmet and acts to cushion the blow. A packing plate is also placed between the pile head and the underside of the helmet, to act as cushion, especially in the case of concrete piles that are likely to suffer damage from the force of the hammer impact. 

Driven piles when necessary are spliced. Figure 5.21 shows typical splices for timber, steel and concrete piles. 

Figure 5.22 shows precast concrete piles fitted with the conventional steel pointed shoes. A flat-ended pile is equally suitable as pointed ended piles in many situations. In the case of piles seated on rock or hard stratum, an Oslo shoe (Figure 5.23) would be suitable. 

Steel-on-steel anvil on either steel or concrete pile 0.50 Cast-iron hammer on concrete pile without cap 0.40... 

MS 1314. 1993. Precast concrete pile. Part 1 General requirement and specifications. Malaysian Standards. Sambhandaraksa, S. Pitupakhorn, W. 1985. Prediction of presstressed concrete pile capacity in stiff clay and clayey sand. Proceedings of 8th South East Asian Geotechnical Conference. Malaysia Kuala Lumpur. 358-363. 

The integrity or quality of a grouted concrete pile can be checked using the acoustic wave method, such as the PIT (Pile Integrity Tester), which is a low stain dynamic testing, or the ground penetrating radar (GPR) technique. 

Figure 11.10. Checking concrete pile integrity using GPR technique (from Kong et al. 1997).

Kong, F.N., Bahia, H.M. Huat, B.B.K. 1997. Radar tomography checking concrete pile integrity. Non... 

In the construction drawings, the approach embankments using local fills were to be supported by 200 mm x 200 mm RC piles with pile-caps. In addition, 6 m long wooden piles were also used between the RC piles for further support of the embankment fill. More wooden piles were also installed on the banks of the river in an attempt to stabilize the lateral displacement of the soft alluvium. The abutments and piers were generally supported by 400 mm diameter spun concrete piles. 

Numerical simulation of heat storage of solar-ground concrete pile... 

ABSTRACT In this paper, established the mathematical model of the process of thermal storage in the solar-ground concrete pile. It adopted finite element methods to numerically simulate the unsteady-state temperature field of concrete pile that around the underground vertical tube, given the calculated format of different boundary condition, analyzed the temperature variation rule of the concrete around heat exchanger. This paper provided reference basis of ascertain method about the bury depth of the vertical U-tube and the mix proportion of the concrete pile. 

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