Overview
Stormwater Systems:
2600 Storm Sewer Construction covers the infrastructure that receives and conveys surface water from both commercial and residential areas within the City. This includes curb inlets, field inlets, junction boxes, pipe, box culverts, and open channels. Improper installation can cause flooding or sinkholes, both becoming large economic issues.
Contract Documents
The City's Design and Construction Manual will be used on development projects and the CIP projects will use the approved plans in the contract. Both areas will have approved submittals of materials including concrete design, precast drawings, castings, manhole steps, reinforcement,and which type of pipe will be allowed.
Submittals
Pipe:
Approved submittals shall be with the inspector at all times in order to make a determination in the field if the proper materials are being used. Generally, HDPE (High Density Polyetheline) and (CMP)Aluminized Corregated pipes are acceptable when not under or near street construction. All other areas use (RCP) Reinforced Concrete Pipe. All pipe products will have the type and manufacturer on it to determine the class. Classes vary depending of factors such as bury depth.
Stormboxes and Box Culverts:
Smaller stormboxes are generally precast and submittals and certifications are to be approved.
Field Observations:
Concrete
All pour in place storm boxes are to be checked for rebar spacing, concrete testing, and verify batch design mix is per specification on the concrete tickets. Check to see if contractor uses a vibrater and verify consolidation after the forms have been stripped. Chisel out "honeycombs" and grout prior to backfill. If the non consolidation is extensive, full replacement may be in order.
If an adjustment is required for the top slab which is less than or equal to 6 inches, the adjustment shall be made with brick and mortar with a coating of cement on both faces, if the adjustment is greater than 6 inches, the adjustment shall be made with dowelled concrete.
Dowels shall be bars embedded 6 inches into the walls. All reinforcement shall be the same size and spacing as the wall steel.
Piping and Appertentences:
Attention to lines and grades are essential. No bends, swags, or humps are allowed. If conflicts occur due to other utilities, contact your construction project manager. Whenever pipe jointing occurs, make sure tar is free of dirt or bedding rock before jointing occurs. Tar will dry out, make sure the contractor does not get too far ahead with this process. Check the spigot and bell ends for chipping. Excessive damage will be cause for rejection. The undamaged portion of pipe can be cut and used as a short piece near boxes.
Pipe requires special backfill along with bedding. Check your specifications for details.
After curbs are poured check curb inlets to see if lids are grouted in place and free of boards, dirt, and debris. Boxes shall be clean prior to installation of inverts.
Storm Boxes and Box Culverts:
Larger boxes and box culverts are poured in place and rebar shall be check for sizing,placement,and free of mud and form oil. All needs to be checked prior to installation of formwork. Spacing against formwork needs checked for clearance and chairs might be needed. All exposed edges shall be chambered. Concrete testing will be done during pours. Curing and stripping of forms will be covered in the specifications. After stripping forms, check for honeycombs, do to lack of vibration, chisel out and grout. Remove snap ties and tar holes prior to backfill. Grind all fins and blemishes on exposed areas that was due to uneven forms.
Documentation
As always, all approved changes in work shall be indicated on both the contractor's and inspector's plans for as-built information to be given to the construction project manager. Complete both diary and material records daily.
Contact Operations and take photos if existing conditions of storm sewer is either deteriorated, damaged, or needs cleaned. Note in the diary of such conditions as pre-existing or contractor damage.