Union Square Chester PA

Friday, June 20, 2008

Field Report Thursday June 19, 2008

June 19, 2008. Low 80's during day, 60's overnight.
Forecast 80's next 5 days, rain Saturday night through Sunday morning, and occasional shower next week.

Lot 1 party wall rebuild

Lot 2 1st floor framing in progress

Lot 3 1st floor framing in progress

Lot 4 1st floor framing in progress

Lot 5 termite shield installation in progress

Lot 6

Lot 7

Field Report June 19, 2008 Building Structural System

Building structural system;

The lateral force resistance for the structure is composed of three primary elements;

Vertical reinforcing in the masonry walls.

Exterior wall shear panels.

Floor and roof panels.

The masonry vertical reinforcing is suspect, see previous wall collapse report.

Exterior shear wall panels must have installed the Simpson strap ties spanning the 2nd floor rim joist, and epoxy anchor bolts to the masonry wall as shown on the framing drawing 2/S1.

The 2nd floor panel must be fully connected with epoxy anchor bolts to the masonry wall, check to confirm all bolts are secure and will not pull out, the triple joist stair well header must be through bolted or lag bolted and provided with a top hung joist hanger with flange nailing to the 2x10 ledger, and all multiple joists must have top hung joist hangers as shown on S1.

The roof truss rake rafter and bottom cord must be epoxy anchor bolted to the masonry wall, including garage roof truss as shown on S1.

All truss to wall plate hurricane ties must be installed and fully nailed as shown on S1.

Not shown on the permit approved set, but will help me sleep at night; add a strap brace to the 2nd floor bathroom walls at the masonry wall and provide (2) epoxy anchor bolts to the bathroom wall panels and the masonry wall.

Site super to advise when the above items are complete on lots 20 through 26 and I will do an inspection report, then follow with 14 through 19, 8 through 13, and 1 through 7, or a sequence that make sense for production.

Stair well opening, use top hung joist hanger at multiple joists.

Stair well triple header at party wall, through or lag bolt triple joist and use top hung joist hanger at ledger with face nail flanges.

Non-typical triple joist condition, solid block space with adjacent close spaced joist and through bolt, top hung joist hanger to ledger.

Field Report Wednesday June 18, 2008 Wall Collapse

June 18, 2008 Lot 1 to lot 2 party wall collapsed. Report delayed to confirm details;

Extended reach forklift operator reported during delivery of a full pallet of 1st floor wall panels to lot 1, one wheel of the forklift settled on a soft patch of soil tipping the load and striking the masonry partywall.
Operator will split loads to at least half pallet for the balance of the project, and halt equipment if any personnel are in the tilt zone of the fork lift.

The wall collapse with failure above the 2nd course, revealed that the vertical rebar stopped in the 2nd course above slab, this rebar was fully grouted. Rebar above the second course was not run into the block course below with rebar and some of the rebar in the wall was clean of grout.

On June 19, 2008 the mason rebuilt the wall.

Options for inspecting the other party walls;

Destructive;
Open 3 or 4 sections of wall on each building to inspect rebar locations and grout fill, this could expand to more locations if rebar and grout is not adequate, then rebuild.

Non-destructive;
MTI can image wall densities to show masonry, grout and rebar. If rebar and grout is inadequate then rebuild. Ambric may also have the equipment for this.

Belt and suspenders;
Assume grout and rebar is inadequate (confirm with some random wall openings or random imaging); bolt steel channel C 3x5 (3" x 1-1/2" x 1/4" thick) at 48" o.c., vertically to the wall exterior including garage, from slab to roof and spanning the bond beam at 2nd floor, with 3/8" dia galvanized through bolts at 32" o.c., with transom washers on the interior face. Furr the exterior for siding with 2x4's same depth as the channel.
Chester L&I may require a P.E. to review.

Lot 1 to 2 partywall collapse June 18,2008

Lot 1 to 2 party wall collapse June 18, 2008

Lot 1 to 2 party wall collapse rebuild, June 19, 2008

Wednesday, June 18, 2008

Field Report Wednesday June 18, 2008

Wednesday 18, 2008
Mid 70's F daytime high, 50's F and 60's F at night, evening thunderstorms over past few days.
High 70's F and low 80's F forecast through to early next week with chance of thunderstorms.