Alex1264
Industrial
- Oct 1, 2002
- 2
Hi
We are erecting a new steel building. The building is 60’ by 40 ‘. The steel supports are placed at 20’ intervals. Largest supporting steelwork is respectively north to south placed at 20’and 40’. The building faces north with a width of 40’ the length is 60’ north to south. We were asked to pour a 3’ foundation, no spec was given for width of foundation so we poured at 16” wide. Where the steel supports are situated we made an area of 3’ square. Because of the site lay we poured part of the foundations to get us to ground level, leaving approx. 18” still to pour. In the foundations were also places rebar 1\2” and incased in wire mesh.
A problem arose so the client decided to have the foundations tested for strength. An engineer came out and used a rebound hammer to test the concrete. His instrument read 2000 psi in all locations.
His recommendation was then to have core samples taken and tested.
Three locations were taken and the following results were given.
CR Unit weight Compressive Strength psi
1 133.8 960
2 133.9 2030
3 120.1 510
All areas tested were poured at the same time using the same mix. We mix our own concrete on site.
Also the test was done at about the 20th day after the pour. Core samples were soaked in a lime/water solution for a min of 24 hours prior to the tests. (Is the normal?).
From these results the engineer has recommended that all the concrete be removed and we start pouring again from scratch following his guidelines.
Can any one please help shed some light on this matter?
As I see the foundations are just not required in the first place.
We are erecting a new steel building. The building is 60’ by 40 ‘. The steel supports are placed at 20’ intervals. Largest supporting steelwork is respectively north to south placed at 20’and 40’. The building faces north with a width of 40’ the length is 60’ north to south. We were asked to pour a 3’ foundation, no spec was given for width of foundation so we poured at 16” wide. Where the steel supports are situated we made an area of 3’ square. Because of the site lay we poured part of the foundations to get us to ground level, leaving approx. 18” still to pour. In the foundations were also places rebar 1\2” and incased in wire mesh.
A problem arose so the client decided to have the foundations tested for strength. An engineer came out and used a rebound hammer to test the concrete. His instrument read 2000 psi in all locations.
His recommendation was then to have core samples taken and tested.
Three locations were taken and the following results were given.
CR Unit weight Compressive Strength psi
1 133.8 960
2 133.9 2030
3 120.1 510
All areas tested were poured at the same time using the same mix. We mix our own concrete on site.
Also the test was done at about the 20th day after the pour. Core samples were soaked in a lime/water solution for a min of 24 hours prior to the tests. (Is the normal?).
From these results the engineer has recommended that all the concrete be removed and we start pouring again from scratch following his guidelines.
Can any one please help shed some light on this matter?
As I see the foundations are just not required in the first place.