No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
For seismic retrofit, in most cases you don't consider the contribution of concrete shear strength in plastic hinge zones anyway. The capacity is derived from the reinforcing steel alone. I am not suggesting to arbitrarily bump the concrete strength by 30% if pushover analysis is OP's end goal (which I doubt that is what they were getting at).
I am writing a small article that explains why steel increases the tensile strength of concrete. I am showing compressive strength since it is often referenced in concrete. In regard to compressive strength of concrete, I will show a range of 2000-3000 psi since that is what we typically use to pour foundations. To summarize, the chart will ...
Would like to make a reasonably precise determination of the expected performance variations of a slab with design strength specified as 3000 psi or 4000 psi mix design. Floor to be reinforced concrete, SOG, with 3k versus 4k being the only variable. Floor is approx 30 ksqft and intended for...
The bond strength was sufficiently high that failure at 23,600 lbs. load was via concrete cracking rather than debonding from the steel. I've never tried converting this type of data before, but as it appears to me from Fig. 2 of ASTM A944 that the test bar bonded length is 12", the total #6 rebar bonded surface area (nominal) is 28.27 sq. in ...
RE: Compressive Strength % of 28-day moist-cured Concrete Chart dicksewerrat (Civil/Environmental) 13 Sep 05 22:50 If you try to publish data that was not actually collected at the time of the break, you are publishing fraudulent data. give the people paying for the tests data you got on day 11,23, or whatever.
The overdesign to achieve the target strength/required average compressive strength f'cr based on trial mixtures or field test record depends on the f'c. According to Table 5.3.2.2, the overdesign can be as low as 1000 psi if f'c is less than 3000 psi. For higher strength ranges the over design increases.
Your anchor is governed by concrete breakout and anchor pullout (also fastener strength, but that is usually more than the concrete failure). If you can use a longer anchor with more embed, the breakout strength will increase, but the pullout strength stays the same. Note that the breakout strength is not a function of the anchor diameter.
That 1930's concrete was every bit as good, or better, than modern 4000 psi concrete. The earlier methods were crude, but workmanship and attention to details (accurate charging of the mixer, vibration, curing, etc.) were superior. IMHO, if the design strength of a pre-1960 structure is known, test samples from the existing structure. The ...
Here is a typical formula for calculating strength based on time for "normal" concrete. You have to know the design or expected f'c. t is time in days since the concrete was cast. f'ci= f'c*(t/(4.00+0.85t)) If you don't know the f'c, back into it using the 7-day break value. Then use that f'c value to calculate your 28-day strength.
We did not, as they were also low and we required testing in accordance with ACI 318-02, Section 5.6.5 - Investigation of low Strength Test Results, ACI 214.4R-03 Guide for Obtaining Cores and Interpreting Compressive Strength Results and ASTM C 42/C 42M-99 Standard Test Method for Obraining and Testing Drilled Cores and Sawed Beams of Concrete.
