734PERMANENT EARTH RETENTION SYSTEM FOR CUT-WALL APPLICATION

WALL APPLICATION

734.01Description

This work shall consist of designing an d constructing a permanent earth retention system utilizing a cut-wa ll application in accordance with 105.03. Cut-wall applications refer to a class of earth rete ntion systems in which construction of the system is performed from the top of the wall to the base utilizing either externally or internally stabilized elements or a combination of both. Geotechnical Engineering Circular No. 2 – Earth Retaining Systems, Report No. FHWA-SA-96-038 provides 10 further discussion of cut-wall applications.

734.02Contractor Design Requirements

The permanent earth retention system utilizing a cut-wall application shall be designed by a professional engineer having experience in the design of at least three completed permanent earth retention systems involving cut-wall applications. The permanent earth retention system shall be designed using the procedure described in the AASHTO LRFD Bridge Design Specifications, or in the FHWA-IF-03-017, Soil Nail Walls. The required partial safety factors or allowable strength factors for Service Load Design, SLD, and load and resistance factors for LRFD, shall be in accordance 20 with the above-referenced publications. The minimum factor of safety for SLD global stability or minimum required LRFD global stability shall be in accordance with the above-referenced publications, unless specified otherwise. Structural design of an individual wall element not addressed in the FHWA report shall be designed in accordance with the AASHTO specifications . Geometric data and design criteria including shear strength parameters and unit weights for soil and rock, corrosion protection, internal and external drainage requirements, horizontal and vertical alignment of the wall, and all known site and construction constraints, wall facing, and facing architectural requirements shall be as shown on the plans.

Design calculations shall include, but not be limited to, the following:

and location, magnitude and direction of design slope, external surcharge loads, and piezometric levels with the most critical 40 slip surface shown along with the minimum calculated SLD factor of safety for global stability or minimum required LRFD global stability soil resistance to load ratio. 734.02

strength parameters and unit weights for soil and rock.

elements.

resistance factors for LRFD used in the design on the pullout resistance, surcharges, unit weights of soil and rock, and all materials proposed for the system including, but not limited to shotcrete, steel, and concrete.

number, wall location and designation, date of preparation, 60 initials of designer and checker, page number shown on each page, and an index page.

computer programs used in the design.

facing and facing connections, including consideration of flexural and shear strength of the facing and all externally stabilized elements, tensile streng th of all headed studs, upper 70 cantilever, minimum reinforcement ratio, mechanical splices, welds, built-up sections, and cover and splice requirements.

The limits of the wall and ground survey data shall be verified before preparing the drawings. Working drawings shall include all details, dimensions, quantities, ground profiles, cross-sections necessary to construct the wall, and the following:

finished face of the wall at its base and at all changes in horizontal alignment.

easement limits, location of all known active and 90 734.02

abandoned existing utilities, adjacent structures, or other potential interferences.

pipe behind, passing through, or passing under the wall.

reference base lines to fix the locations of the 100 explorations relative to the wall.

and vertical break points, and at least every 30 ft along the wall.

facing. 110

the base of the wall.

as vertical and horizontal spacing.

facing expansion and contraction joints along the wall length.

front of the wall.

and all special construction requirements, such as dewatering, 130 if required.

points.

734.02

centerline stationing.

of each wall showing estimated square feet of exposed wall face 140 areas and other pay items.

elements, and corrosion protection details.

the orientation and dimensional relationships of the unbonded and bonded lengths.

internally stabilized elements, reinforcing bars, steel welded wire reinforcement, bearing plates, headed studs, and attachment devices for pneuma tically placed mortar, cast-in- place, or prefabricated facings.

coping, drainage gutters, and fences.

for permanent facing elements.

The Contractor shall submit working drawings and design calculations in accordance with 105.02.

At least 30 calendar days before the star t of the wall construction, the Contractor 170 shall submit a QCP which will be subject to approval. The QCP shall include, but not be limited to, personnel qualifications, wall construction procedures and sequencing, a verification testing program, and a performance monitoring program. Work shall not begin until written notice has been received from the Engineer that the QCP has been accepted.

The field superintendent or field forema n shall have supervised the construction of a minimum of three completed walls of the same type as that submitted by the Contractor. 180

734.02

The program shall include a verification testing program of all production and test anchors and nails. The program shall identify the test locations and the type of test, such as proof, performance, or pullout, testing procedures, acceptance criteria, and load and measuring devices to be used.

MATERIALS

734.03Materials 190

Materials shall be in acco rdance with the following:

Geotextile Under Riprap .............................................. 918.02 Steel H Piles ................................................................ 915.02 Steel Pipe Piles ............................................................ 915.01 Steel Sheet Piling ......................................................... 910.21 Structural Steel ............................................................ 910.02 200 Structure Backfill ........................................................ 904.05 Uncoated Seven-Wire Strand ...................................... 910.01(b)7 WWR, Smooth a nd Deformed..................................... 910.01

Drainage pipe shall be underdrain pipe in accordance with 715.02(d).

CONSTRUCTION REQUIREMENTS

734.04General Requirements

Excavation and embankment shall be in accordance with 203. 210

Welding shall be in accordance with 711.32.

734.05Performance Monitoring During Construction

The program shall identify points of m onitoring interest, in accordance with Geotechnical Engineering Circular No. 2 – Earth Retaining Systems, Report No. FHWA-SA-96-038, and the frequency of monitoring during and following construction of the wall. The program shall also include a baseline survey for points of monitoring interest.

The Contractor shall notify the Engineer if indications of ground movement in the vicinity of the wall, increased size of old cracks, or separation of joints in structures, foundations, streets, or paved or unpaved surfaces are observed. The Contractor shall monitor the performance of the wall and movements of buildings, roads, or other facilities within a distance of three times the excavation depth for the wall. If the Engineer determines that the movements exceed those anticipated for construction, the 734.05

Contractor shall take corrective actions n ecessary to arrest the movement or make repairs.

Within 30 days after completion of the work, as-built drawings shall be submitted 230 to the Engineer. Revised design calculations, signed by the professional engineer, shall be provided for all design changes made during the construction of the permanent earth retention system.

734.06Performance Monitoring After Construction

Performance monitoring by the Contractor shall be accomplished during construction and for a period of one year from the date the Contractor has been relieved of further maintenance, as set out in th e final acceptance letter from the Department. The Contractor shall post a warranty bond for the performance monitoring that occurs after the Contractor has been relieved of further maintenance. The Contractor shall 240 make evaluations of the test and monitoring data and performance of the wall at the frequency defined in the approved performance monitoring program. The Contractor, if necessary during the monitoring period or as directed, shall correct deficiencies in the capacities of individual elements or take other corrective measures which may be required to prevent damage or excessive movement of the wall and adjacent facilities. The Contractor shall submit all test and monitoring data to the Engineer on a weekly basis or as otherwise directed.

734.07Method of Measurement

Cut wall will be measured by the square foot of exposed face area of wall above 250

finished grade as shown on the plans.

734.08Basis of Payment

The accepted quantities of cut wall will be paid for at the contract unit price per

square foot for cut wall.

Payment will be made under:

Pay Item Pay Unit Symbol

260

Cut-Wall, No. ____ ................................................................... SFT

The costs of all professional services, labor, excavation, structure backfill,

equipment, materials, tests, and QCP shall be included in the cost of this work. All

incidentals necessary to design, construct, and monitor the wall including all drainage

required by the wall design and all temporary construction facing or permanent facing,

if applicable, and correction required by the wall design of deficiencies which may be

required to prevent damage or excessive movement of the wall shall be included in the

cost of this work. No additional payment will be made for the costs of providing and

taking corrective actions.270

734.06