Chapter 5.75
DEMOLITION AND ABANDONMENT OF LINES AND STRUCTURES
Sections:
5.75.030 Salvage of equipment and materials.
5.75.040 Methods and equipment.
5.75.050 Removal of old structures.
5.75.060 Abandonment of pipelines.
5.75.070 Sewer structures to be abandoned.
5.75.080 Disposal of materials and debris.
5.75.010 Description.
The contractor shall remove equipment and concrete work as necessary for the construction of work and abandon certain pipelines and structures as shown on the plans and as specified. [Ord. 2014-2 (Att. § 15-01).]
5.75.020 Safety.
The contractor shall take all necessary precautions with regard to safety in carrying out the demolition work. Suitable barriers shall be erected around the demolition area to protect workmen and the public, and the contractor shall rigorously comply with applicable safety requirements. [Ord. 2014-2 (Att. § 15-02).]
5.75.030 Salvage of equipment and materials.
All electrical and mechanical equipment and piping designated to be salvaged shall be carefully salvaged and delivered to the District in good condition. When designated on the plans or in the special provisions, the contractor shall give the District two working days to remove sensitive electrical equipment. Salvaged materials shall not be reused in new work unless specifically permitted by the District. [Ord. 2014-2 (Att. § 15-03).]
5.75.040 Methods and equipment.
Before starting work, the contractor shall inform the District fully as to the method of demolition he proposes to follow, and the amount and character of equipment he proposes to use, which shall be subject to the approval of the District. The approval of the District shall not be considered as relieving the contractor of the responsibility for the safety of his method or equipment or from carrying out the work in full accordance with the plans and specifications. [Ord. 2014-2 (Att. § 15-04).]
5.75.050 Removal of old structures.
The contractor shall carefully dismantle old structures which, unless otherwise provided in the special provisions. [Ord. 2014-2 (Att. § 15-05).]
5.75.060 Abandonment of pipelines.
Pipelines to be abandoned shall be filled with grout and securely closed at all pipe openings by a watertight plug of concrete, or brick and cement mortar, not less than three feet thick.
The grout materials for filling pipelines shall consist of Portland cement, or Portland cement and fly ash with additives to enhance maximum flowability without bleeding or segregating.
(1) The grout shall have a minimum compressive strength of 25 psi in 24 hours when tested in accordance with ASTM C-403 and a minimum compressive strength of 100 psi in 28 days and maximum compressive strength of 150 psi in 28 days when tested in accordance with ASTM C-495 or C-109.
(2) The contractor shall establish the proposed grout mixes, methods, plans and criteria that the grouting operations shall meet. The grouting system shall have sufficient gauges, monitoring devices and tests to determine the effectiveness of the grouting operation and to ensure complete fill (100 percent) and that no voids exist within the pipeline or structure.
(3) One or more mixes shall be developed to completely fill the abandoned pipe/structure and to meet the following requirements:
(a) Accommodate the diameter or size of pipe/structure.
(b) Accommodate the void size of the surrounding soil.
(c) Accommodate the absence or presence of ground water.
(d) Provide the acceptable strength and durability.
(e) Provide load bearing capacity.
(f) Shrinkage shall not exceed two percent by volume.
(4) The contractor shall design a grout mix with a maximum density of 65 PCF, while at the same time maintaining apparent viscosity not to exceed 18 seconds as tested in accordance with ASTM C-939. The ultimate load bearing capacity shall be 36 tons/square foot minimum. [Ord. 2014-2 (Att. § 15-06).]
5.75.070 Sewer structures to be abandoned.
Sewer structures to be abandoned shall have all openings, sewer lines, inlets and outlets sealed off, and the structure shall be removed to a point three feet below the proposed street grade or ground surface and filled with intermediate backfill material compacted to 90 percent relative compaction.
The surface shall be restored as shown on the typical trench section shown on the plans. Where manholes to be abandoned are in landscaped areas, an approved top soil mix shall be placed in the top 12 inches and the landscaping shall be restored.
The manhole frame and cover from existing manholes to be removed or abandoned shall not be reused on new manholes and shall become the property of the contractor.
Manholes designated to be removed shall be excavated, all castings, covers, barrel sections and the base shall be completely removed and disposed of at a legal disposal site. The excavation shall be backfilled with intermediate backfill material and compacted as necessary for the final surfacing. [Ord. 2014-2 (Att. § 15-07).]
5.75.080 Disposal of materials and debris.
All materials and debris resulting from the demolition work and after salvage by the District shall become the sole property of the contractor and shall be disposed of by the contractor at a legal disposal site. [Ord. 2014-2 (Att. § 15-09).]