Engineering Updates

HOW TO CALCULATE BEARING CAPACITY OF SHALLOW FOUNDATION IN SAND FROM SPT VALUES OR N-VALUES  (IS-6403) STEP-1 Perform standard penetration test  on the location for which you want to calculate bearing capacity. This is done as per standard procedure given in IS-2131. Standard penetration test must be done at every 75 cm in vertical direction. STEP-2 Decide the depth, width and length of foundation for initial calculation. This is a trial and error process. In the first attempt, you can never get the exact size of foundation which will satisfy all of your needs. STEP-3 Apply necessary  corrections to the standard penetration test values . Calculate the cumulative average value of corrected SPT values from the base level of foundation to a depth equal to 2 times the width of foundation. STEP-4 Correlate the above cumulative average SPT value with the fig given below to find out the corresponding angle of shearing resistance (ϕ). Relation between ph...

According to the Concrete Reinforcing Steel Institute (CRSI), “form work and its associated labor is the largest single cost segment of the concrete structural frame—generally more than 50%.”           • maintaining constant depth of horizontal construction           • maintaining constant spacing of beams and joists           • maintaining constant column dimensions from floor to floor           • maintaining constant story heights Standard Forms Since most projects do not have the budget to accommodate custom forms, basing the design on readily available standard form sizes is essential to achieve economical form work. Also, designing for actual dimensions of standard nominal lumber will significantly cut costs. A simplified approach to form work carpentry means less sawing, less piecing together, less waste, and less time. this results in reduced labor and mated costs and fewer op...

Things that are discussed and attended during the concept design stage: • T ype of construction — reinforced concrete, precast concrete, reinforced masonry, structural steel, cold formed steel, wood, etc. • Column locations — A uniform grid facilitates repetitive member sizes, reducing the cost and increasing the speed of construction. Bay dimensions may also be optimized to minimize material quantities while efficiently accommodating specific space requirements, such as parking garages and partition layouts. • Bracing or shear wall locations — Horizontal forces due to wind, earthquakes, etc. must be transferred down from the superstructure to the foundations. The most efficient means of accomplishing this is usually to provide vertical bracing or shear walls oriented in each principle direction, which must be coordinated with functional and aesthetic requirements for partitions, doors, and windows. • Floor and roof penetrations — Special framing is often required to accom...