Section 254 — Soldier Pile Retaining Walls

Description

254.01This work consists of constructing permanent soldier pile retaining walls.

254.02Definition. For soldier pile retaining walls, a lift is defined as a stable height of unsupported excavation before installation of lagging.

Material

254.03Conform to the following Section and Subsections: Geocomposite drain Piling Reinforcing steel Welded stud shear connectors 714.02 715 709.01 717.05

Construction Requirements

254.04Qualifications . Provide an engineer or geologist, a supervisor , and foreperson with experience installing soldier pile retaining walls. At least 30 days before starting soldier pile retaining wall work , submit the following for approval:

(a)Professional engineer or geologist. A résumé for a professional engineer or professional geologist with at least 2 years’ experience logging subsurface profiles of soldier pile retaining wall or drilled shafts, and documenting construction and testing results ;

(b)Engineer or geologist. If applicable, a résumé for a geotechnical engineer or engineering geologist working under the direct supervision of the professional engineer or professional geologist described in Subsection 254.04(a) ; and

(c)Supervisor and foreperson . A résumé for each individual describing their experience on at least five soldier pile retaining wall projects of similar size and complexity within the past 10 years. Include project names, locations, and contact information for project owners.

254.05Submittals. At least 30 days before starting the soldier pile wall installation work, submit the following according to Subsection 104.06:

(a)Start date;

(b)Description of equipment and methods of excavation, hole stability, cleanout, spoils containment, and pile installation;

(c)Retaining wall construction sequence;

(d)Structural steel types, sizes, and details. Include lifting bracket, support bracing or anchor locations, and centralization methods; (e) Descriptions of concrete and backfill materials and placement methods;

(f)Drilling method and details for ground anchors according to Subsection 256.04;

(g)Temporary lagging design details, backfill materials, drainage materials, and method of installation;

(h)Reinforcing steel bar order lists and bending diagrams according to Subsections 104.06 and 554.03; and

(i)Production certificates with each shipment of piles and lagging.

254.06General . Survey according to Section 152 and verify limits of wall installation. Provide an engineer or geologist to log subsurface mat erial condition descriptions from the ground surface to the bottom of the shafts. Conform to Section 257 for Contractor -designed soldier pile walls.

254.07Soldier Pile Installation. If driven piles are specified, insta ll according to Section 551. Drive or drill pile to the elevation shown in the plans or approved drawings. When drilling, perform the following:

(a)Drill through material to bottom of shaft elevation shown in the plans or app roved drawings. If caving conditions are encountered, do not excavate further until implementing the method to prevent ground caving as described in the approved drawings. Do not leave more than 2 inches of loose or disturbed material in the bottom of the hole for soldier piles with permanent ground anchors, or more than 12 inches of loose material for soldier piles without permanent ground anchors.

(b)Install steel soldier pile in the drilled hole. Position and center the steel soldier pile to maintain the specified minimum concrete cover.

(c)Construct structural concrete according to Section 552, and flowable backfill according to Section 614. If multiple types of concrete or backfill are specified, place the specified material in the lower section to specified elevation. Allow the concrete to initially set to sufficient strength before placing the next type of concrete or backfill. Do not dri ll adjacent holes for 12 hours after backfilling.

(d)Place the specified upper concrete or backfill to the specified upper elevation. Pump out water or place concrete or backfill using a tremie pipe if more than 6 inches of water is present at the time of concrete or backfill placement.

(e)Use the on -site engineer or geologist to log the drilling and ground conditions with depth. Note advancement rates, seepage zones and rates, drilling fluid, casing type and depth, drilling methods and equipment used, installat ion notes, concrete or backfill placement methods, and remarks.

(f)Place the centerline of the steel soldier piles so that the top is within 1 inch of the plan location and plumb to within 0.5 percent of the length based on the total length of the pile.

254.08Excavation and Lagging Installation.

(a)Excavation. Excavate for the wall in staged lifts concurrent with lagging installation. Do not allow the exposed unsupported final excavation face cut height to exceed 6 feet or the short- term stand -up height of the g round, whichever is less. Provide a soil face during excavation with a smooth contact surface for the lagging. Backfill caving areas with approved material.

(b)Lagging. Provide timber lagging according to Section 557 and as sh own in the plans or approved drawings. Place lagging boards behind the front flange of the soldier pile overlapping the end of the lagging by at least 3 inches on both ends of the lagging boards. Secure the lagging board to prevent slippage as indicated in the plans or approved drawings. Provide a gap between boards as shown in the plans or approved drawings. Install the lagging tight up against the excavated soil. If the excavation caves or is not even enough to install the lagging tight up against the soil, backfill using the method and materials in the approved drawings to accommodate subsurface drainage. Do not install lagging more than 3 feet below the level of the ground anchors before installation of the anchors.

254.09Backfill Installation . Backfi ll behind the lagging according to the approved drawings before continuing excavation. Repeat this process until excavation reaches the elevation as shown in the plans or approved drawings. Do not excavate more than 3 feet below ground anchor elevations and the bottom of lagging elevation.

254.10Geocomposite Sheet Drain Installation. Install geocomposite sheet drain system according to Section 605. 254.11 Permanent Ground Anchors. Where permanent ground anchors are requ ired, provide permanent ground anchors and bearing assemblies conforming to Section 256 as shown in the plans or approved drawings. Install all anchors at similar levels before excavation to the next level anchors. Do not e xcavate to next level anchors until all anchors at prior level are locked off. Perform proof test and performance test of anchors according to Section 256.

254.12Concrete Fascia Wall. If a cast -in-place concrete facing is specified:

(a)Install falsework according to Section 562.

(b)Install headed studs along the soldier pile beam as shown in the plans and according to Subsection 555.13.

(c)Install reinforc ing steel according to Section 554.

(d)Install structural concrete according to Section 552.

254.13Final Backfill. Backfill to final grade behind and in front of the wall with the specified material shown in the plans or approved drawings.

254.14Acceptance. Material for soldier piles will be evaluated under Subsections 106.02 and 106.03. Construction of soldier piles will be e valuated under Subsections 106.02 and 106.04. Concrete will be evaluated under Section 552. Driven piles will be evaluated under Section 551. Temporary works will be evaluated under Section 562. Flowable backfill will be evaluated under Section 614. Geocomposite sheet drain systems will be evaluated under Section 605. Permanent ground anchors will be evaluated under Section 256. Steel structures will be evaluated under Section 555. Survey will be evaluated under Section 152. Timber structures will be evaluated under Section 557.

Measurement

254.15Measure the Section 254 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring soldier piles by the linear foot, measure from the top of steel soldier pile elevation to the pile tip or bottom of shaft elevation, whichever is greater.

Payment

254.16The accepted quantities will be paid at the contract price per unit of measurement for the Section 254 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 .