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Бетонные работы

Method Statement: Construction of a Monolithic Reinforced Concrete Retaining Wall

Professional technological documentation regulating the construction process of monolithic reinforced concrete retaining walls using framed formwork. The method statement establishes strict engineering requirements for geodetic layout, earthworks, foundation preparation, and concreting using modern mechanization adapted to international standards (ISO, EN).

6 sections 67 figures

Materials

Concrete mix class C12/15 - C15/20 (equivalent to B15), W6, F100
Deformed reinforcing steel Ø10 mm (class 400/500 MPa)
Electrodes for manual arc welding Ø4.0 mm
Edged softwood lumber (thickness 15 and 25 mm)
Reinforced LDPE polyethylene film (width 2000 mm, 200 µm)
Non-woven synthetic geotextile (density 450 g/m2)
Crushed granite stone, fraction 20-40 mm (strength grade M800)
Building sand (fineness modulus as per design)

Equipment

Backhoe loader (bucket volume 0.28 m3, digging depth up to 5.46 m)
Dump truck (load capacity 13.0 t)
Mobile boom crane (load capacity 25.0 t)
Transit mixer (useful volume 4.5 m3)
Swiveling concrete bucket ('Shoe' type, volume 1.0 m3)
Three-phase gasoline generator (380/220 V, 11 kW, weight 150 kg)
Welding generator (single-operator, 200 A, 230 V, weight 90 kg)
Reversible/forward vibratory plate compactor (force/weight 90 kg, depth up to 150 mm)

1. General Provisions and Design Parameters

This method statement is developed for a complex of construction and installation works on the erection of retaining walls (volume of works V=100 m3), used for terracing, zoning, erosion protection, and slope stabilization. The structure ensures the protection of road embankments, shorelines, and foundations from the impact of lateral movements of heaving soils. The works are carried out by a mechanized crew in one shift.

The design dimensions and embedment depth of the structure strictly depend on the wall height and soil type. For walls with a height of 0.4–1.5 m, the formwork and wall body are embedded by 1/3 of the total height. With a wall height of 1.6–2.0 m, the minimum embedment is 0.7 m. The minimum thickness of the trapezoidal wall in the upper part is 10 cm.

The base (footing) width is calculated based on the soil bearing capacity: for sandy soils and sandy loams (loose soil), it is 1/2 of the height (1:2); for loams (medium density soil) — 1/3 of the height (1:3); for dense clay soils — 1/4 of the height (1:4). To reinforce and stabilize, the use of galvanized double-twisted metal wire meshes in combination with the main reinforcement cage is permitted.

Fig. 1 — Load charts for a mobile crane indicating lifting capacities for various boom lengths (9.7m, 15.7m, 21.7m) and jib extensions (6m, 9m) across different working radii.

Analysis of design documentation and determination of the required ratio of wall dimensions to soil type.
Verification of the technological readiness of the construction site and the availability of a work permit.
Arrangement of temporary access roads, storage areas, and provision of electricity to the site.

2. Labor Organization, Crew Composition, and Material and Technical Supply

To ensure the specified pace and quality of work, a complex team of 6 people is involved. The composition includes: two 4th-grade formwork carpenters, two 3rd-grade specialists, and two 2nd-grade general laborers. A mandatory requirement is the availability of slinger certificates for at least two members of the brigade. All workers must possess the skills to assemble reinforcement cages and tie knots according to ISO 17660 standards.

Material provision includes concrete mix of international class C12/15 or C15/20 (equivalent to B15), with water resistance grade W6 and frost resistance F100. Reinforcement is carried out with deformed steel bars with a diameter of 10 mm (class 400/500 MPa). Softwood lumber (thickness 15 and 25 mm), reinforced LDPE film (thickness 200 µm, width 2000 mm), crushed granite stone of 20-40 mm fraction (crushability grade M800), and non-woven geotextile with a density of 450 g/m2 are also used.

The mechanization set includes: a backhoe loader (bucket 0.28 m3, digging depth 5.46 m), a dump truck with a load capacity of 13 t, a mobile boom crane (25 t), a transit mixer (4.5 m3) with a swiveling concrete bucket (1.0 m3). Auxiliary equipment: three-phase gasoline generator (11 kW, 150 kg), welding generator (200 A, 230 V), internal vibrators, gasoline vibratory screed (1.2 m, 1.2 HP), and a vibratory plate compactor (weight 90 kg, compaction depth up to 150 mm).

Fig. 1 — General arrangement and principal mechanical components of a heavy-duty diesel-powered backhoe loader — Fig. 2 — General arrangement and principal mechanical components of a heavy-duty diesel-powered backhoe loader

Conducting safety inductions and distributing work assignments among the comprehensive crew members.
Deployment of mobile power stations (11 kW) and checking equipment grounding.
Preparation of the concrete bucket and inspection of the mobile crane's rigging equipment.

3. Geodetic Layout and Axis Fixing

The geodetic layout basis is accepted by an act with reference to a global or local system of coordinates and elevations. The layout is carried out in two planes: horizontal (position of axes and outline in plan) and vertical (elevations from benchmarks). The reference point for linear structures along roads is the axis of the carriageway.

The fixing of axes on the site is carried out using reusable beacons driven into the ground and a stretched steel wire (or string). To ensure the safety of the layout basis for the period of earthworks and concrete works, an inventory batter board is installed at a distance of 2–3 meters from the contour of the future trench.

Vertical elevations are transferred using a dumpy level. The surveyor transfers the layout basis to the site manager, who is responsible for its preservation. Any displacements of the beacons are unacceptable and require a repeated instrumental check. Upon completion of the stage, a certificate of inspection of the geodetic layout basis is signed.

Fig. 1 — KamAZ heavy-duty dump truck showing cab, chassis, and hydraulic rear-tipping cargo body — Fig. 3 — KamAZ heavy-duty dump truck showing cab, chassis, and hydraulic rear-tipping cargo body

Acceptance of geodetic control points from the Client (at least 10 days before the start of works).
Setting out the longitudinal and transverse axes of the wall on site, fixing them with control pegs.
Installation of inventory batter boards at a safe distance (2-3 m) and stretching of the axial strings.
Transfer of elevations from the working benchmark to the elements of the batter boards.

4. Earthworks and Trench Excavation

The excavation of a rectangular trench is carried out by a backhoe loader below the normative soil freezing depth. For bulk soils, the freezing depth is taken at 1.7 m, for loamy soils — 1.45 m (parameters are adjusted according to local climatic norms). The trench width at the bottom should be 0.5 of the design wall height. Soil excavation is carried out with dumping into a spoil heap or directly into dump trucks.

The excavation is performed with an under-digging to the design elevation. The final leveling of the trench bottom is done exclusively manually according to the profile and level, removing excess or adding missing soil. It is strictly forbidden to grade and compact frozen soil, as well as soil containing snow and ice.

Compaction of the soil subgrade is carried out by a vibratory plate compactor (weight 90 kg) in 8 passes per track. The process continues until a compaction coefficient of at least 0.98 is achieved. The quality of work is confirmed by instrumental control and the execution of a concealed works inspection certificate.

Fig. 1 — General view of a heavy-duty off-road concrete mixer truck detailing chassis, mixing drum, and auxiliary concrete handling systems. — Fig. 4 — General view of a heavy-duty off-road concrete mixer truck detailing chassis, mixing drum, and auxiliary concrete handling systems.

Dismantling of interfering axial strings while strictly preserving control beacons.
Mechanized soil excavation by a backhoe loader leaving a protective layer.
Manual leveling of the trench bottom to design elevations with level control.
Compaction of the thawed soil base with a vibratory plate compactor (minimum 8 passes) to K=0.98.

5. Installation of a Drainage Bedding Layer

To drain moisture from the concrete structure and prevent frost heaving, a drainage bedding layer is arranged. A non-woven synthetic geotextile (density 450 g/m2) is spread along the compacted trench bottom. The material is laid with an overlap and mandatory wrapping onto the vertical trench walls to the height of the future sand and crushed stone preparation.

Building sand is delivered by dump trucks to the on-site storage, from where it is moved into the trench by a backhoe loader. The distribution of sand over the geotextile is done manually (with shovels and spreaders). To achieve the design thickness of the compacted layer h=0.15 m, sand is dumped with a thickness of h=0.17 m in a loose state (an initial loosening coefficient K=1.10 is applied).

Compaction of the sand layer is carried out by a vibratory plate compactor with layer-by-layer moistening if necessary. After acceptance of the sand cushion, a crushed stone layer (fraction 20-40 mm, grade M800) is arranged in a similar way, over which a blinding concrete layer is poured, serving as a reliable waterproofing barrier and an even base for formwork installation.

Fig. 1 — General arrangement of a portable electric concrete mixer showing mixing drum, structural frame, drive unit, and tilt control mechanisms — Fig. 5 — General arrangement of a portable electric concrete mixer showing mixing drum, structural frame, drive unit, and tilt control mechanisms

Laying geotextile rolls along the trench bottom fixing the edges on the slopes.
Feeding building sand into the trench and manual leveling taking into account the loosening coefficient (1.10).
Compaction of the sand with a vibratory plate compactor to a design thickness of 150 mm.
Dumping crushed stone of 20-40 mm fraction and pouring a blinding concrete layer for cage installation.

6. Formwork, Reinforcement, and Concreting Works (Overview Cycle)

Installation of the inventory framed formwork is carried out on the prepared concrete base observing the concrete cover of the reinforcement (using polyethylene spacers). The reinforcement cage is assembled from deformed steel bars (10 mm), connections are made by manual arc welding (4.0 mm electrodes) or tying wire. Formwork panels are fixed with tie rods and push-pull props to withstand the hydrostatic pressure of the concrete mix.

The pouring of concrete class C15/20 (W6, F100) is carried out using a transit mixer and a swiveling concrete bucket with a capacity of 1.0 m3, moved by a mobile crane. The placement of the mixture is carried out in horizontal layers with a thickness not exceeding the length of the working part of the internal vibrator. Compaction is considered sufficient when the mixture stops settling, air bubbles cease to emerge, and cement paste appears on the surface.

Curing of freshly poured concrete includes covering it with reinforced LDPE film (thickness 200 µm) to prevent moisture loss. Formwork removal is performed only after the concrete has reached stripping strength (according to international standards for monolithic concrete). The final stage is the waterproofing of the rear face of the wall with roll materials (roofing felt, membranes) and the backfilling of the excavated spaces with draining soil.

Fig. 1 — Components of a motorized vibrating screed for concrete leveling and compaction — Fig. 6 — Components of a motorized vibrating screed for concrete leveling and compaction

Installation of reinforcement meshes and spatial cages fixing the concrete cover.
Installation and alignment of inventory formwork panels, treatment of the deck with anti-adhesive release agent.
Concreting the structure in layers with mandatory vibration using internal vibrators.
Concrete curing (covering with LDPE film), subsequent formwork removal and waterproofing.

Fig. 1 — Components of a walk-behind vibratory plate compactor equipped with a water sprinkle system — Fig. 7 — Components of a walk-behind vibratory plate compactor equipped with a water sprinkle system

Fig. 1 — Components and layout of a portable fuel-powered electrical generator — Fig. 8 — Components and layout of a portable fuel-powered electrical generator

Fig. 1 — General arrangement and key components of a portable gasoline-powered electrical generator — Fig. 9 — General arrangement and key components of a portable gasoline-powered electrical generator

Fig. 1 — Portable internal concrete vibrator assembly showing drive unit, flexible shaft, and vibrating head — Fig. 10 — Portable internal concrete vibrator assembly showing drive unit, flexible shaft, and vibrating head

Fig. 1 — Technical cross-section of an L-shaped reinforced concrete retaining wall detailing the structural reinforcement, multi-layer drainage system, and foundation preparation — Fig. 11 — Technical cross-section of an L-shaped reinforced concrete retaining wall detailing the structural reinforcement, multi-layer drainage system, and foundation preparation

Fig. 1 — Layout diagram for excavation setting out using batter boards and string lines — Fig. 12 — Layout diagram for excavation setting out using batter boards and string lines

Fig. 1 — Configuration of an electrical grounding network and equipotential bonding system — Fig. 13 — Configuration of an electrical grounding network and equipotential bonding system

Fig. 1 — Isometric view of a concrete strip element with vertical reinforcement dowels spaced at 1000 mm intervals. — Fig. 14 — Isometric view of a concrete strip element with vertical reinforcement dowels spaced at 1000 mm intervals.

Fig. 1 — Perspective view of a trench excavation showing the leveling layer and reinforcing mesh for a foundation slab — Fig. 15 — Perspective view of a trench excavation showing the leveling layer and reinforcing mesh for a foundation slab

Fig. 1 — Cross-sectional detail of a composite reinforced concrete slab with permanent formwork and integrated shear trusses — Fig. 16 — Cross-sectional detail of a composite reinforced concrete slab with permanent formwork and integrated shear trusses

Fig. 1 — Sequential manual tying process for orthogonal reinforcing steel bar intersections using annealed wire and a manual tying hook — Fig. 17 — Sequential manual tying process for orthogonal reinforcing steel bar intersections using annealed wire and a manual tying hook

Fig. 1 — Precast concrete foundation block with embedded lifting loops for hoisting and placement. — Fig. 18 — Precast concrete foundation block with embedded lifting loops for hoisting and placement.

Fig. 1 — Types of plastic reinforcement spacers for maintaining concrete cover in reinforced concrete structures — Fig. 19 — Types of plastic reinforcement spacers for maintaining concrete cover in reinforced concrete structures

Fig. 1 — Reinforcement detailing for a concrete foundation slab with vertical starter bars. — Fig. 20 — Reinforcement detailing for a concrete foundation slab with vertical starter bars.

Fig. 1 — Details of mechanical wedge clamp assemblies used for non-welded lap splices and orthogonal cross-connections of structural reinforcement bars — Fig. 21 — Details of mechanical wedge clamp assemblies used for non-welded lap splices and orthogonal cross-connections of structural reinforcement bars

Fig. 1 — Step-by-step procedure for executing a diagonal lashing knot on intersecting cylindrical members — Fig. 22 — Step-by-step procedure for executing a diagonal lashing knot on intersecting cylindrical members

Fig. 1 — Sequence of tying intersecting reinforcement bars with wire and nippers — Fig. 23 — Sequence of tying intersecting reinforcement bars with wire and nippers

Fig. 1 — Preparation of foundation base showing concrete leveling course, reinforcement mesh, and spacer blocks prior to structural concrete placement — Fig. 24 — Preparation of foundation base showing concrete leveling course, reinforcement mesh, and spacer blocks prior to structural concrete placement

Fig. 1 — Prefabricated reinforced concrete structural panel with openings and integrated fastening points — Fig. 25 — Prefabricated reinforced concrete structural panel with openings and integrated fastening points

Fig. 1 — Formwork assembly for reinforced concrete trench or foundation wall — Fig. 26 — Formwork assembly for reinforced concrete trench or foundation wall

Fig. 1 — Components of a standard reusable formwork tie rod assembly for reinforced concrete wall construction — Fig. 27 — Components of a standard reusable formwork tie rod assembly for reinforced concrete wall construction

Fig. 1 — Isometric diagram and detail view of parallel reinforced concrete walls structurally connected by welded transverse steel tie rods — Fig. 28 — Isometric diagram and detail view of parallel reinforced concrete walls structurally connected by welded transverse steel tie rods

Fig. 1 — Isometric view of wooden formwork assembly for a continuous concrete foundation wall, detailing panels, studs, ties, and lateral bracing elements. — Fig. 29 — Isometric view of wooden formwork assembly for a continuous concrete foundation wall, detailing panels, studs, ties, and lateral bracing elements.

Fig. 1 — Isometric diagram of a braced timber formwork assembly for a continuous reinforced concrete channel structure — Fig. 30 — Isometric diagram of a braced timber formwork assembly for a continuous reinforced concrete channel structure

Fig. 1 — Pouring of a concrete foundation using a suspended hopper and modular formwork system — Fig. 31 — Pouring of a concrete foundation using a suspended hopper and modular formwork system

Fig. 1 — Cross-section showing the consolidation of a concrete mixture using a deep vibrator within supported formwork — Fig. 32 — Cross-section showing the consolidation of a concrete mixture using a deep vibrator within supported formwork

Fig. 1 — Cross-section detail of a post-installed steel anchor embedded 180mm into a reinforced concrete substrate through thermal insulation and vapor barrier layers — Fig. 33 — Cross-section detail of a post-installed steel anchor embedded 180mm into a reinforced concrete substrate through thermal insulation and vapor barrier layers

Fig. 1 — Isometric view of a cast-in-place reinforced concrete foundation slab detailing vertical starter bars and main vertical reinforcement for a corner wall structure — Fig. 34 — Isometric view of a cast-in-place reinforced concrete foundation slab detailing vertical starter bars and main vertical reinforcement for a corner wall structure

Fig. 1 — Sequential procedure for manual tying of reinforcing steel bars in a lap splice using annealed tie wire and a twisting hook tool — Fig. 35 — Sequential procedure for manual tying of reinforcing steel bars in a lap splice using annealed tie wire and a twisting hook tool

Fig. 1 — Layout of vertical reinforcement and support structure for a reinforced concrete wall on a foundation slab — Fig. 36 — Layout of vertical reinforcement and support structure for a reinforced concrete wall on a foundation slab

Fig. 1 — Sequential procedure for tying intersecting reinforcing bars using a specialized twisting tool. — Fig. 37 — Sequential procedure for tying intersecting reinforcing bars using a specialized twisting tool.

Fig. 1 — Plastic wheel-type rebar spacers for maintaining concrete cover in vertical reinforced concrete structures — Fig. 38 — Plastic wheel-type rebar spacers for maintaining concrete cover in vertical reinforced concrete structures

Fig. 1 — Assembly of modular wall formwork with internal corner panel and horizontal waler system on a concrete foundation — Fig. 39 — Assembly of modular wall formwork with internal corner panel and horizontal waler system on a concrete foundation

Fig. 1 — Rigging and hoisting configuration for modular large-area wall formwork panels, illustrating lifting components and temporary plumbing struts — Fig. 40 — Rigging and hoisting configuration for modular large-area wall formwork panels, illustrating lifting components and temporary plumbing struts

Fig. 1 — Assembly of modular wall formwork with adjustable diagonal supports on a concrete foundation — Fig. 41 — Assembly of modular wall formwork with adjustable diagonal supports on a concrete foundation

Fig. 1 — Assembly diagram of modular panel formwork system for straight and corner vertical concrete walls — Fig. 42 — Assembly diagram of modular panel formwork system for straight and corner vertical concrete walls

Fig. 1 — Construction of a monolithic concrete wall showing formwork assembly, concrete pouring bucket, and integrated work platform — Fig. 43 — Construction of a monolithic concrete wall showing formwork assembly, concrete pouring bucket, and integrated work platform

Fig. 1 — Cross-section of vertical formwork illustrating the internal vibration method for consolidating freshly poured concrete in layered placements — Fig. 44 — Cross-section of vertical formwork illustrating the internal vibration method for consolidating freshly poured concrete in layered placements

Fig. 1 — Isometric view of wall formwork assembly with scaffolding brackets and vertical reinforcement — Fig. 45 — Isometric view of wall formwork assembly with scaffolding brackets and vertical reinforcement

Fig. 1 — Assembly and vertical stacking of large-panel formwork system for cast-in-place concrete walls, detailing panel connections and alignment hardware — Fig. 46 — Assembly and vertical stacking of large-panel formwork system for cast-in-place concrete walls, detailing panel connections and alignment hardware

Fig. 1 — Isometric view and detail of a retaining wall system with an anchored concrete slab and steel cable tensioning assembly — Fig. 47 — Isometric view and detail of a retaining wall system with an anchored concrete slab and steel cable tensioning assembly

Fig. 1 — Detail of a structural connection using a metal bracket and mechanical anchors embedded in a concrete substrate — Fig. 48 — Detail of a structural connection using a metal bracket and mechanical anchors embedded in a concrete substrate

Fig. 1 — Detail of formwork tie system securing a vertical panel against an existing wall structure — Fig. 49 — Detail of formwork tie system securing a vertical panel against an existing wall structure

Fig. 1 — Isometric view of a single-sided wall formwork system supported by diagonal braces anchored to a foundation slab. — Fig. 50 — Isometric view of a single-sided wall formwork system supported by diagonal braces anchored to a foundation slab.

Fig. 1 — Isometric and cross-sectional views demonstrating the installation and stabilization of large-panel wall formwork — Fig. 51 — Isometric and cross-sectional views demonstrating the installation and stabilization of large-panel wall formwork

Fig. 1 — Penetration test using a graduated cone to determine material consistency — Fig. 52 — Penetration test using a graduated cone to determine material consistency

Fig. 1 — General arrangement and component detailing of an industrial work positioning safety belt and adjustable lanyard system — Fig. 53 — General arrangement and component detailing of an industrial work positioning safety belt and adjustable lanyard system

Fig. 1 — Standardized kinetic communication protocol detailing slinger positioning and the 'Hoist/Raise Load' visual hand signal for mobile crane hoisting operations — Fig. 54 — Standardized kinetic communication protocol detailing slinger positioning and the 'Hoist/Raise Load' visual hand signal for mobile crane hoisting operations

Fig. 1 — Standard operational hand signaling for mobile cranes: 'Lower Load' command execution — Fig. 55 — Standard operational hand signaling for mobile cranes: 'Lower Load' command execution

Fig. 1 — Standard hand signal for crane operations: 'Stop' — Fig. 56 — Standard hand signal for crane operations: 'Stop'

Fig. 1 — Standard hand signal for hoisting a load during mobile crane operations — Fig. 57 — Standard hand signal for hoisting a load during mobile crane operations

Fig. 1 — Standardized hand signaling for crane operations detailing the 'Lower load' command executed by a qualified rigger — Fig. 58 — Standardized hand signaling for crane operations detailing the 'Lower load' command executed by a qualified rigger

Fig. 1 — Standard crane hand signal for swinging the boom — Fig. 59 — Standard crane hand signal for swinging the boom

Fig. 1 — Standard hand signal for crane operation: 'Stop' or 'Secure the load' — Fig. 60 — Standard hand signal for crane operation: 'Stop' or 'Secure the load'

Fig. 1 — Material handling operations: Mobile truck crane lifting and positioning a large-diameter utility pipe onto a stepped storage stack using two-point rigging. — Fig. 61 — Material handling operations: Mobile truck crane lifting and positioning a large-diameter utility pipe onto a stepped storage stack using two-point rigging.

Fig. 1 — Standardized geometric designs and iconography for industrial safety and warning signs — Fig. 62 — Standardized geometric designs and iconography for industrial safety and warning signs

Fig. 1 — Elevation view of a temporary rope safety barrier with suspended warning signs — Fig. 63 — Elevation view of a temporary rope safety barrier with suspended warning signs

Fig. 1 — Proper deployment and load distribution setup for mobile crane outriggers, including manual extension, pad bearing on timber cribbing, and full operational stance. — Fig. 64 — Proper deployment and load distribution setup for mobile crane outriggers, including manual extension, pad bearing on timber cribbing, and full operational stance.

Fig. 1 — Minimum safety clearance requirements for mobile crane operation near stationary structures — Fig. 65 — Minimum safety clearance requirements for mobile crane operation near stationary structures

Fig. 1 — Illustration of a mobile crane lifting a precast concrete element with safety barriers in place — Fig. 66 — Illustration of a mobile crane lifting a precast concrete element with safety barriers in place

Fig. 1 — Determination of the danger zone boundary for a mobile crane based on lifting height and load dimensions — Fig. 67 — Determination of the danger zone boundary for a mobile crane based on lifting height and load dimensions

Tips & Recommendations

It is strictly forbidden to grade and compact frozen soil, as well as soil containing snow and ice. This will lead to critical subsidence of the structure during thawing.

When arranging the sand bedding layer, always consider the sand loosening coefficient K=1.10. To obtain a 150 mm compacted cushion, pour 170 mm of loose sand.

Axial beacons and strings (wire) of the geodetic layout must not shift during earthworks. Before operating heavy machinery, stretch control strings only during the check.

To prevent the leakage of cement paste and siltation of the drainage layer, be sure to wrap the edges of the non-woven geotextile (450 g/m2) onto the vertical walls of the trench.