TU Mate Swe

 Standard Pentratiom Testing on Site The test uses a thick-walled sample tube, with an outside diameter of 50.8 mm and an inside diameter of 35 mm, and a length of around 650 mm. This is driven into the ground at the bottom of a borehole by blows from a slide hammer with a mass of 63.5 kg (140 lb) falling through a distance of 760 mm (30 in). The sample tube is driven 150 mm into the ground and then the number of blows needed for the tube to penetrate each 150 mm (6 in) up to a depth of 450 mm (18 in) is recorded. The sum of the number of blows required for the second and third 6 in. of penetration is termed the "standard penetration resistance" or the "N-value". In cases where 50 blows are insufficient to advance it through a 150 mm (6 in) interval the penetration after 50 blows is recorded. The blow count provides an indication of the density of the ground, and it is used in many empirical geotechnical engineering formulae. Driving Pipe Part1 Taking Result Part2 

Selecting Footing Size and Reinforcement. Most foundation failures are related to excessive movement rather than loss of load-carrying capacity. In recognition of this fact, settlement control should be the first issue addressed. Once service loads have been calculated, foundation plan dimensions should be selected to limit bearing pressures to those that are expected to provide adequate settlement performance. Maintaining a reasonably consistent level of service load-bearing pressures for all of the individual footings is encouraged since it will tend to reduce differential settlements, which are usually of more concern than are total settlements. Once a preliminary footing size that satisfies serviceability criteria has been selected, bearing capacity can be checked. It would be rare for bearing capacity to govern the size of footings subjected to sustained loads. However, where large transient

 Development length and Lap length addresses the length of the bar needed to transfer the stresses to the other bar whereas Development length addresses the length of the bar needed to transfer the stresses to the concrete. Development length Usually at the end of the section where you have forces in the bar, you need to make sure that bar pullout failure doesn’t happen. In order to resist forces in rebar it has to be embedded in concrete. A development length is the amount of rebar length that is needed to be embedded or projected into concrete to create a desired bond strength between the two materials and also to develop required stress in steel at that section. In the example below we require development length of 10db at the end of the section so that bond between concrete and steel remain continuous. As there is no space at the end of the section bar is bent. Notice that 90 degree configuration is used here more configurations can also be used. For further detail refer to ACI or

Orginal By Ko Aung Su Myat