concrete tech

 Expansion Joint in Concrete        Structures in which marked changes in plain dimension take place abruptly shall be provided with expansion on joints at the section where such change occur.  Expansion joints shall be so provided that the necessary movement occur with minimum resistance at  the joint . the structures adjacent to the joint should preferably by supported on separated on separate column and walls but not necessarily on separate foundations . Reinforcement shall not extend across an expansion joint break between the sections shall be complete. why expansion joint required  The details as to the length of a structure where expansion joints have to be provided can be determined after taking into consideration various factors such as temperature exposure to weather the time and season of the laying of the concrete etc . normally structures exceeding 45m in length are designed with one ore more expansion joints . however in view of the large number factors involved in decidi

  Longitudinal reinforcement in Column The cross - sectional area of longitudinal reinforcement , shall be not less than 0.8 present nor more then 6 percent of the gross cross -sectional area of the column . in any column that has large cross-sectional area than that require to support the load the minimum percentage of shall based upon the area of concert requested to resist the direct stress and upon the actual area  The minimum number of longitudinal bars provide in a column shall be four in rectangular column shall be rectangular column in six circular column  The bar shall not be less then 12 mm in diameter  Reinforcement concrete column having helical reinforcement shall have at list six bars of longitudinal reinforcement within the helical reinforcement in a helically reinforcement column the longitudinal bars shall be in contact within the helical reinforcement .and equidistant around its inner circumference  spacing of longitudinal bars measured along the peripheric of the sha

  What is Development Length of Bars The calculate tension or compression in any bar at any section shall be development on each size the section by any appropriate development length or end anchorage or by combination thereof . Development length of Bars Ld Ld = ɸ x   бa /4 X τ bd Where ɸ = Nominal dia of the bars   бa = stress in the bar in the consider in design load τ bd = design load bond stress  Design bond stress in limit state method for plain bar Grade of concrete M20 M25 M30 M35 `M40 Design bond stress τ bd N/mm 2 1.2 1.4 1.5 1.7 1.9 For deformed bars conforming to IS 1786 this value conforming to IS 1786 this value shall be be 60 percent  for bras in compression, the values of bond stress for bars in tension shall be inceeased by 25 percent . Example : assume stress in a bar consider 550D M30 concrete ,and dia is 20mm Ld = ɸ x   бa / 4 x τ bd Ld =20

Pile integrity Test Procedure   The purpose of this study was to test the test piles under Routine load. The design load on the pile is 43.0 T as computed based upon static analysis. The pile is to be tested for vertical compression up to 1.5 times the design load (65.0 ton) or failure, whichever is earlier. The test results have been analyzed to evaluate the safe load on test pile. The test pile is RCC Bored-cast-in-situ of 600 mm diameter and 11.2m length. TEST PROCEDURE FOR VERTICAL COMPRESSION TEST              The procedure for the test was in general accordance with IS:2911 (Part- IV) -1985. The reaction for applying compression load on the test pile is taken by kentledge method to transfer the load on test pile by sand bags. The test load was applied on the pile top by means of a hydraulic jack using plate girders with synchronized electric pumping unit.   The load is measured with the help of a calibrated load gauge attached t

Cube test of concrete as per is code Pouring of empty cube mold for compressive strength of concrete as per pressured follows  by IS code 516 M25 =28.3 N/mm2 M30=34.13N/mm2 M40=44.125 N/mm2 M45=49.125 N/mm2 Size cube 1. 150 X 150 X 150 2. 100 X 100 X 100 Procedure of filing mold 3 step pouring after one step 16mm tempering rod 35 stock .generally used size as site 150 X 150 X150 .after 20 hrs removed mold curing 7 days. Sample taken 0 to 5 cum one set 6 to 15 cum two set 16 to 30 cum three set  31 to 50 cum four set  Every 50 cum one set sample taken .one set is 3 number . If when we are testing one set cube for 7 days and one set cube for 28 days . Target strength of concrete For 28 days  Strength =fck +0.825× standard dilation For M30 standard deviation is 5 For 7 days  60 percentage of our 28 days target strength  SI Code   1. 456:2000 for testing of concrete 2. 516 for poring of concrete Test specimen  Three test specimen shall be made for each sample for testing at 28 days .additi

What is Brick wall construction cost india ? Wall construction coast is 1 cum brick wall  including material like Bricks and sand cement and labor coast. (A)Number of Brick for 1 cum and cost  For 1 cum brick work 0.23 persent is motor and 0.77 persent is Bricks . As per Treditional brick  0.77÷(0.23mm x 0.11mm x 0.076mm = 400 Nos Bricks  Coast is per Bricks 14 Rupees for first class bricks =400x 14  =5600/- Rupees (B)Cement coast  :- Wet volume motore is 0.23 cum And dry volume =0.23 x 1.33=0.31 cum Cement=0.31/0.035 (For cemet unit weight is 1450 , so 50/1450=0.035 volume) =8.85 Bag 1 Bag 8ndian Rupees 450 =8.85x 450 =3982/- Rupees  ( C) Sand coast:- Wet volume motore is 0.23 cum And dry volume =0.23 x 1.33=0.31 cum Sand = 0.31cum =0.31x 35.31 =10.95 cft Indiad average 1 cft Sand 18 Rupees  10.95x 18 =197/- Rupees  ( D) Labour coast   1 cum Brick work will be labour coast average 1000/- Rupees  Total Brick work coast Indian = A+B+C+D =5600+3982+197+1000 =10779/- 🇮🇳 india Rupees  No

Terrace water proofing        For Resist the run off water or rain fall . give good long life of slab . with out roof treatment leakage of water and first damage the steel . Providing and applying Hybrid polyurea WH 200 FOSROC or Conirroof of BASF or equivalent with following specification  Surface preparation             All Surface to be water proofed should be sound clean and dry. All high spots Should be removed. Surface to be finish to a smooth texture by mechanical means. Moss and lichen (if any) must be removed Physically followed by treatment with fungicidal wash to kill any spores and inhibit future growth after treatment wash down thoroughly with clean water and allow to dry. Localized Treatment of Crack :  FOSROC nitocote VF Epoxy Putty or equivalent Shall be apply to fill any hair line cracks, pot holes and other undulation using meatal float manually on damaged mother surface ( where ever required ) after proper mixing the base and hardener and after 24 hrs. Buffing machin