Case Studies

CASE STUDY # 1: 66 DAMAGED BALCONIES DURING CONCRETE CUTTING
LOCATION: – SAN FRANCISCO, CA.

PROBLEM:
Due to a layout error a core drilling crew cut through vital structural reinforcement that supported 66 balcony concrete members. 112 #8 rebar were cut while coring 3″ diameter cores. The damage to the steel reinforcement Concrete coring and concrete cutting in the bay areacompromised the structural integrity of all damaged balconies.

SCOPE OF WORK:
SAFE2CORE Concrete Scanning and Concrete Cutting crews were called in to scan and chip all damaged balconies to identify the location of all surrounding rebar and post-tension cables prior to performing the needed structural repair work.

SOLUTION:
SAFE2CORE crews work alongside the structural steel contractor to chip all 122 damaged rebar locations. SAFE2CORE scanned all damaged areas using Ground Penetrating Radar (GPR) and hand-chipped all areas congested with post-tension cables to prepare all areas for repair work. The structural steel contractor was able to drill into the balconies, insert and weld 122 #8 rebar sectional pieces. After review by the engineering team of the project all balconies were declared repaired and full structural integrity of all balconies were restored. All areas were patched by a concrete contractor.

CASE STUDY # 2: 30 CORROSION MONITORS LOST IN NEW SKYWAY BAY BRIDGE
LOCATION: – OAKLAND/SAN FRANCISCO, CA

PROBLEM:
30 Corrosion monitors embedded in the supporting piers of the new bridge at under sea level locations were not properly installed. The monitors were not wired to the monitoring station before the piers were poured and thus their location was unknown after the pour. Due to building code requirements all monitors needed to be in working order in all piers. These monitors are vital to verify that the structural reinforcement of the supporting piers do not suffer excessive corrosion that could weaken the bridge’s structural integrity over time.Concrete Scanning Bay area and northern california

SCOPE OF WORK:
SAFE2CORE crews were hired to investigate all potential locations in order to find the corrosion monitors. Our Concrete Scanning technicians, using Ground Penetrating Radar (GPR), spent countless hours and exhaustive work under extremely dangerous conditions in confined spaces scanning to try to locate all monitors.

SOLUTION:
After experimenting with different inspection techniques, and to the surprise of our client, who had spent days chipping away at the concrete using as-built plans as a reference to try to expose the monitors, our crews successfully located the lost monitors. This project is to date one of the most challenging inspection projects in which our staff has participated.

CASE STUDY # 3: POST-TENSION CABLE CUT BY CARELESS CONCRETE CUTTING CREW.
LOCATION: – OAKLAND, CA

PROBLEM:
A vital post-tension cable was cut by a concrete cutting crew that failed to follow our instructions before coring into a post-tensioned deck.
Concrete Scanning, X-Ray, GPR, bay area, California
SCOPE OF WORK:
SAFE2CORE crews were hired to repair the severed post-tension cable and restore the structural integrity of the elevated pt slab.

SOLUTION:
The damaged post-tension cable was scanned and traced by one of our Concrete Scanning crews before repair work. After accurately locating the damaged post-tension cable and other surrounding reinforcement, our post-tensioning repair crew chipped away the concrete, repaired the damaged tendon and patched the area. After review by our client’s Senior Construction Superintendent, the post-tensioned slab structural integrity was deemed fully restored.

CASE STUDY # 4: COLUMN REINFORCEMENT LOCATATED PRIOR TO DRILLING CORES FOR PLUMBING LINES
LOCATION: – SAN FRANCISCO, CA

PROBLEM:
Several cans were not put in place by the plumbing contractor during the pour at this jobsite around 4 column lines. 10 6″ cores needed to be drilled to install waste lines around the columns, which are typically congested with reinforcement , both rebar and post-tension cables.
Rebar Locating and concrete scanning in the bay area

SCOPE OF WORK:
SAFE2CORE Concrete Scanning and Concrete Cutting crews were hired to scan and cut all the areas surrounding these columns in order to core without damaging vital structural reinforcement.

SOLUTION:
Our Concrete Scanning crews were dispatched to the jobsite to map the reinforcement prior to coring. Using Ground Penetrating Radar and electronic utility locators, SAFE2CORE located and mapped all embedded targets prior to coring. Our concrete cutting crews cut all 10 6″ cores safely without any damage to rebar, post-tension cables, or conduits.

CASE STUDY # 5: SEVERAL PENETRATIONS PLACED WITHIN MILIMITERES OF POST-TENSION CABLES
LOCATION: – OAKLAND, CA
Utility Locating and Concrete scanning in California
PROBLEM:
Our client needed to place several cores in areas adjacent to post-tension cables. Due to design limitations these cores could not be relocated elsewhere.

SCOPE OF WORK:
SAFE2CORE Concrete Scanning and Concrete Cutting crews were hired to scan all the areas that needed cores put in place prior to coring.

SOLUTION:
SAFE2CORE Concrete Scanning crews located all post-tension cables and our concrete cutting crews cut all cores needed. Some cores were placed within millimeters of post-tension cables without causing any damage.

CASE STUDY # 6: 250 CORING LOCATIONS RELOCATED DUE TO ERROR BY ARCHITECT DURING DESIGN
LOCATION: – SAN FRANCISCO, CA

PROBLEM:
The architect at this construction project erroneously placed more than 250 cores in a 10-story residential edifice. De to this error the plumbing contractor misplaced all cans before all the post-tensioned elevated slabs were poured in place.
GPR, Ground penetrating radar, Bay Area

SCOPE OF WORK:
SAFE2CORE Concrete Scanning and Concrete Cutting were called in by the general contractor at this project to scan and cut all 250 plus cores. The pt decks varied in thickness from 6” to 18”.

SOLUTION:
SAFE2CORE Concrete Scanning crews scanned all coring locations over a period of 60 days prior to concrete cutting. All coring locations needed RFI approval from the project structural engineer before any coring could be performed. SAFE2CORE scanned and cut more than 250 cores at this site. During this job, due to an error of miscommunication, one of our coring crews severed one post-tension cable. SAFE2CORE took full responsibility for the error and our pt-cable repair crew restored the structural integrity of the pt-deck by repairing the cable within 24 hours of damaging the tendon.

CASE STUDY # 7: 22 COLUMNS SUSPECTED OF HAVING INSUFFICIENT REINFORCMENT
LOCATION: – SAN JOSE, CA

PROBLEM:
The structural engineer at this project suspected that the reinforcement stirrups placed around 22 structural columns was insufficient.
Utility locating in the Bay Area
SCOPE OF WORK:
The general contractor chipped two column areas to verify the architect’s suspicion and found that indeed the stirrups put in place during the pour were of the incorrect length.SAFE2CORE Concrete Scanning crews were hired by the general contractor to map all 22 columns and determine the length of each stirrup,12 stirrups per column for a total of 264 sectional pieces.

SOLUTION:
SAFE2CORE Concrete Scanning crews scanned all columns and measured the length of each stirrup. After reviewing our findings, by the engineering team at this project decided that the reinforcement was enough to support the edifice properly and the structural integrity of the building was deemed to be within code requirements.

CASE STUDY # 8: LOCATION OF PT- CABLES DEAD ENDS AND BURSTING STEEL IN 200 FEET OF THE EDGE OF A PT DECK
LOCATION: – DUBLIN, CA

PROBLEM:
50 anchors 1″ dia. x 6″ deep needed to be drilled along the edge of a post-tensioned deck for glazing work, The dead end of post several post-tension cables were located along the edge of the structural slab.
Concrete coring by Safe 2 core in California
SCOPE OF WORK:
The steel contractor at this project hired our Concrete Scanning crews to locate more than 25 post-tension cable dead ends and bursting steel reinforcement prior to drilling the anchors into the edge of the structural slab.

SOLUTION:
SAFE2CORE (Concrete Scanning) crews using Ground Penetrating Radar scanned over 200 feet of the edge of this structural slab to locate all dead ends and bursting steel reinforcement prior to drilling. All anchors were successfully drilled by the steel contractor without any damage to vital structural reinforcement.

CASE STUDY # 9: 60 CORES SCANNED AND DRILLED INTO PRE-STRESSED CONCRETE
LOCATION: – PALO ALTO, CA

PROBLEM:
60 3″ dia. cores needed to be drilled in this Tenant Improvement project in Palo Alto, CA. to install new electrical, data , HVAC, and plumbing lines.
Utility Locating and GPR ground penetrating radar
SCOPE OF WORK:
The general contractor at this project hired our crews to locate all reinforcement prior to concrete cutting. Our concrete scanning crews needed to perform all scans from below in an overhead position since a topping slab with wire mesh had been poured on top of the precast concrete planks. The wire mesh obstructed the view of our scanners when the scanning was performed on the surface of the topping slab.

SOLUTION:
SAFE2CORE Concrete Scanning crews using Ground Penetrating Radar (GPR) scanned 32 precast planks prior to concrete cutting. More than 60 cores were cut by SAFE2CORE concrete cutting crews without any damage to bonded pre-stress tendons or any other vital steel reinforcement.

CASE STUDY # 10: SAFE2CORE HIRED TO RE-SCAN WORK INACCURATELY PERFORMED BY ANOTHER SERVICE PROVIDER.
LOCATION: – PALO ALTO, CA

PROBLEM:
The general contractor at this project hired one of our competitors to scan several areas in structural walls and slabs prior to concrete cutting. The concrete cutting contractor hired to cut cores for plumbing lines cut several pieces of rebar and notified the general contractor.
Concrete scanning and Concrete coring in california
SCOPE OF WORK:
The general contractor decided to call our Concrete Scanning crews to rescan all the previous work performed by one of our competitors at this project.

SOLUTION:
SAFE2CORE Concrete Scanning crews using Ground Penetrating Radar (GPR) re-scanned all areas. As the picture on the left clearly shows, SAFE2CORE was able to re-scan all areas and properly mark all structural reinforcement. Concrete cutting proceeded without incident after our crews completed our survey at this project.