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Section 19 – Trench Excavation, Bedding and Backfill

the Contractor’s control, the stronger pipe or improved bedding and backfill shall be provided at

the Contractor’s expense.

19-1.02.C Water Pipe

Water pipe minimum and maximum trench widths shall be as shown on Standard Drawing

8-17 unless otherwise shown or specified in the Contract. If trench widths at the top of the pipe

are exceeded by any amount, the Contractor shall provide stronger pipe or improved bedding

and backfill conditions, as approved by the Agency to meet the changed load requirements. If

the trench width is exceeded for any reason within the Contractor's control, the stronger pipe or

improved bedding and backfill shall be provided at the Contractor's expense.

19-1.03 Pavement Cutting

When the trench is in an existing paved area, the pavement shall be saw cut on neat lines

parallel and equidistant from the trench centerline. The width of the saw cut shall not be any

greater than is required to properly install the pipe and not damage the edges of the pavement

left in place, or as directed by the Agency. Pavement between the lines shall be broken and

removed as directed by the Agency immediately ahead of the trenching operations. The

existing pavement shall be removed in conformance with Standard Drawing 4-31. Top backfill

in existing paved areas shall conform to Standard Drawing 4-31.

Pavement shall not be cut until the respective utility companies have marked the location of

their underground facilities and the Agency has given final approval of the trench alignment.

19-1.04 Maximum Length of Open Trench

Unless otherwise specified in these Specifications or the Special Provisions, at the end of

each Working Day, there shall be a maximum of three hundred feet (300’) of trench allowed to

remain open in unimproved areas, excluding manhole excavations, for each operation unless

otherwise authorized by the Agency. The remainder of the trench shall be backfilled and

compacted, and when in streets, opened to traffic as soon as possible. The maximum length of

trench open for cast-in-place concrete pipe shall be as specified in Section 36-3, “Trench

Excavation”, of these Specifications.

19-1.05 Control of Water

Control of water shall conform to the requirements in Section 10-5, “Control of Water in the

Work”, of these Specifications.

19-1.06 Shoring and Bracing

The Contractor shall furnish and install sufficient shoring and bracing to insure the safety of

personnel and public, protect the Work, and protect adjacent improvements. Contractor must

comply with all of the requirements of Section 6-20, “Excavation and Trench Safety”, of these

Sheeting shall not extend below the bottom of the pipe barrel. Unless otherwise specified in

the Special Provisions or required by the Agency, all sheeting, timbering, lagging, and bracing

shall be removed during backfilling, and in such a manner to prevent any movement of the

ground or damage to the pipe or to other structures. When the Agency requires that sheet

piling, lagging, and bracing be left in place, such materials shall be cut off where designated and

the upper part withdrawn. If steel piling is used, it may be removed simultaneously with placing

and compacting of backfill.

When using movable trench supports, care shall be exercised to prevent disturbing the pipe

location, jointing, or embedment. Removal of any trench protection below the top of the pipe

and within two and one-half (2-1/2) pipe diameters of each side of the pipe will be prohibited

after the pipe embedment has been placed and compacted. Movable trench supports shall only

be used in either wide trench construction where supports extend below the top of the pipe or

on a shelf above the pipe with the pipe installed in a narrow, vertical wall subditch. Any voids