In pile driving operation, proper selection of piling hammers is essential to prevent the damage of piles. For instance, a light hammer with higher drop causes a higher impact stress than a heavy hammer with lower drop provided that they generate the same energy per blow.
What are the functions of cap block, drive cap and pile cushion in driven piles?
Cap block is installed between the hammer end and the drive cap to control the hammer blow in order to protect both the hammer and the pile from damage. When the hammer hits the cap block, it compresses elastically and reduces the peak forces, thereby lengthening the time of hammer blow. Moreover, it should be capable of transmitting the hammer energy effectively to the piles.
Is Hiley’s formula suitable for estimating capacities all driven H-piles?
In Hong Kong, the local practice of driven H-piles is to adopt dynamic formula like Hiley’s Formula to drive piles to set and verify its capacity by static load test for a certain proportion of these piles.
Is Hiley’s formula suitable for clayey soils?
The basis of all dynamic formulae is the conservation of energy in which energy applied to the piling system by driving hammer is equal to the energy required to penetrate the soils with energy losses during the process. The Hiley’s formula is the most popular dynamic formula used in Hong Kong.
How do rock sockets take up loads?
The load transfer mechanism is summarized as follows:
When a socketed foundation is loaded, the resistance is provided by both rock socket wall and the socket base and the load distribution is a function of relative stiffness of foundation concrete and rock mass, socket geometry, socket roughness and strength. At small displacements the rock-socket system behaves in an elastic manner and the load distribution between socket wall and socket end can be obtained from elastic analysis.
What is the value of micropiles when compared with bored piles and driven piles?
Micropiles are defined as bored piles with diameters not exceeding 250mm. Micropiles were first constructed in Italy in 1950s and were given the name “root piles”.
Whenever bored piles (larger diameter) and driven piles are considered feasible, they should be more economic than micropiles. Owing to the small size of piles, only small dimension of equipment is needed for construction. Moreover, it can be used to drill through any type of soils, boulders and hard materials.
What is the purpose of shaft grouting for friction barrettes?
For the construction of friction barrettes, some grout pipes are designed at the periphery of the barrettes. Within a short duration (e.g. 24 hours) of concreting of barrettes, the fresh concrete cover is cracked by injecting water.
What is the purpose of post-grouting for mini-piles?
Post-grouting is normally carried out some time when grout of the initial grouting work has set (e.g. within 24 hours of initial grouting). It helps to increase the bearing capacity of mini-piles by enhancing larger effective pile diameter. Moreover, it improves the behaviour of soils adjacent to grouted piles and minimizes the effect of disturbance caused during construction. In essence, post-grouting helps to improve the bond between soils and grout, thereby enhancing better skin friction between them.
China International Construction Machinery Exhibition (CME2011)
With the support of the Republic of China Ministry of Housing and Urban, China Association of Municipal Machinery Association will hold “China International Construction Machinery Exhibition 2011” (CME 2011) at Guangzhou-Canton Fair Pazhou Complex in March 30th-April 1st,2011. So this exhibition will integrate the industry resources of construction machinery from all dimension, enhance brand value and strengthen the core competitiveness of intellectual property greatly. It also set up an international full-service platform for construction machinery industry and constantly improve manufacturers’ international competitiveness.
By more than one year’s market research, CME 2011 has fully learned the aspirations of the majority of construction machinery manufacturers. Therefore,CME 2011 will take the “Asia’s largest” Canton Fair- Pazhou Complex in Guangzhou as a platform. CME 2011 is expected to cover over 50,000 square meters, including indoor exhibition hall and outdoor exhibition hall, which will gather more than 50,000 professional visitors and industry representatives from over 20 countries and regions.
The more exciting news is “China Association of Municipal Engineering Annual Conference” will be held at the same time with the CME 2011.All members of China Association of Municipal Engineering will be present at this Exhibition, including Municipal Engineering Association in various provinces, autonomous regions and municipalities, units of municipal road engineering design, construction, maintenance, management, administrative department of transportation, Road and Bridge Companies, Municipal Engineering Company and so on. They will form a powerful and professional purchasing team, which is unparalleled in any exhibition in China.
Meanwhile, it is a blue moon for all decision-making figures of China Association of Municipal Engineering gathering to attend an exhibition, which will give you unexpected surprise to propagandize your product in here and to demonstrate your enterprise image here. Besides, Municipal authorities, management and other related departments, industry will also attend this grand exhibition., so it will bring out an extraordinary effect in China municipal engineering.
Simultaneous activity
China Municipal Engineering Association Annual Conference
Related forums, exchange meeting, technology promotion meeting and other supporting activities.
The 3rd Guangzhou International Garden Landscape & Better Living Fair
For further details, please contact:
Vicky Cai
Tel No.:+86 20-22106420
Fax No.+86 20-82579220
E-mail:[email protected]
Concrete Mix Design – M70 Grade of Concrete (OPC 53 Grade)
Concrete mix design – M70 grade of concrete provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.
A. Design Stipulation:
Characteristic comprehensive Strength @ 28 days = 70 N/mm2
Maximum size of aggregate = 20 mm
Degree of workability = Collapsible
Degree of quality control = Good
Type of exposure = Severe
Minimum cement content as per is 456-2000