Method Statement for Surveying Works of Land Projects

method-statement-survey

What is Method Statement for Surveying Works?

The Method Statement for Surveying Works is the process of detailing how setting-outs and survey works will be carried out in construction projects. This includes the established key methods of control to show how the work will be managed which ensures that the nominated tolerances and quality are achieved. The task will be done according to the specifications and approved drawings.

The survey activities include are as follows but not limited to:

  • Initial survey to validate site/plot boundaries; permanent markers are established and site data is collected.
  • Demarcation of the project area and marking of the limits and boundaries.
  • Set out for vertical and horizontal control of precast elements, in-situ concrete slab, raft foundations, wall, columns, formworks, storm drainage, trenches, kerbs, and other structures.
  • Setting out of grid lines and taking records of the actual ground level in preparation for excavation
  • Horizontal Control & Vertical Survey Control
  • Transfer of datum
  • As-built surveys

I will be implementing the method statement for survey works with the project located in Qatar. All of the relevant terms associated with the country’s surveying practices are mentioned. Nonetheless, if the method statement for other countries will be adopted be advised to check with the specific practices intended for the country and modify the method statement accordingly.
As long as the task and conditions do not change, generic work method statement may be used at a number of civil engineering projects.

Method Statement for Surveying – Procedure

General
This methodology covers the requirement for setting out and survey of the works which include locating existing services, accurate setting-out of the alignments and positions on-site, surveying the site and establishment of temporary benchmarks, checking the slopes of excavated surfaces to facilitate the construction activity.

Before the activity or any part thereof are commenced, the Contractor and the Consultant Engineer shall together make a complete survey and take grade levels of the site and agree with the Consultant Engineer on all particulars upon which setting out of the works will be based, including existing plant, buildings, and services. Moreover, a risk assessment must be conducted by the contractor prior to the start of the concerned work.

The Contractor shall prepare shop drawings detailing all survey information and survey levels. Such levels shall be related to the temporary benchmarks as aforesaid. The plans shall also show the site’s permanent grid lines. After an agreement of the drawings, they shall be signed by the Consultant Engineer and Contractor and will form the basis of settling out.

During site formation and construction of structural elements such as slab, column, foundation, wall, etc. the surveyor is responsible for accurate setting-out of their alignments and positions on-site.

Setting-out is allowed to proceed only when construction drawings with sufficient information have been finalized and approved by the consultant. The surveyor should ensure the latest and sufficient setting-out data are received. The surveyor should also check the main dimensions and reconcile them by adding intermediate dimensions given in the drawings.

Working “from whole to part”, the survey control point should be established on undisturbed and permanent features such as walls, concrete foundations, curb line, etc.

The network of closed traverses which start from and established by closed onto different known control points is recommended as the accuracy of the survey result can be evaluated and refined by using adjustment methods in computation.

Setting Out , Levels, and Reference Grids

surveyor setting out the project work
Surveyor setting out the area

Control Stations
Control Stations (PBM) to be provided from MMUP/GIS (Ministry Municipality and Urban Planning / Geographical Information System) as performed by 3rd Party Surveyor. (The independent company which provides design teams with a complete range of land surveying and topographic services.)

The survey control is based on the following geodetic reference system
Projection UTM Zone 39
Spheroid WGS 84
Plan Datum WGS 84
Height Datum WGS 84 Ellipsoid/QND95
Units Meter
Scale Factor 0.99999

Site control stations will be placed around the construction site in strategic locations where they will not be disturbed by construction activities and secondary control will be placed closer to the work area. These will be made up of monument type as:
K1. Steel Pin, in Concrete

A steel pin 30 centimeters long with a diameter of 1 centimeter buried vertically inside a concrete block of 30 x 30 x 30 centimeters size, with 2 centimeters protruding above the concrete surface. Point number is usually inscribed on the concrete.

For the survey detail, GNSS coordinates are required for the TBM’s, and static or fast Static GNSS survey will be used for the control network.

Due to their location and proximity to work activities, they are more likely to be disturbed and will need to be checked at regular intervals. Checks will be done on every use by connecting to no less than two other stations.

In case of controls being disturbed, the contractor shall replace them whether on the same position or some other positions approved by the surveyor consultant.

The project site is connected to Permanent Bench Mark (PBM) provided by the client representative through 3rd party surveyor.

The points have been cross-checked for relative position and found to be correct.

If required, further site control would be established as necessary by closed loop traverse.

All precise work must be linked to the four permanent marks formed around the site via closed traverse and/or level run.

Plan Control
Static GPS observations will be used to establish a minimum of two survey stations. Following that, the data will be post-processed to generate grid co-ordinates and height above datum. Rather than using less accurate Real-Time Kinetic (RTK) measurements, this would be preferable.

Closed-loop enclosed by closed traverse will be used to create additional site control as required. With PK or Hilti nails in hard material or Perma Marks in soft material, a minimum of two Permanent Ground Markers (PGMs) would be identified

Temporary Bench Marks
From the given control points as located by an approved 3rd Party Surveyor, Temporary Bench Marks (TBM) will be established sufficient for the purpose of the topographical survey, construction works level control, and elevation determinations.

TBM’s shall also be connected to the national grid values (QND95).

New TBM Installation shall be K1. Steel Pin, in Concrete

Barriers around the Temporary Bench Mark shall be used for protection from the moving equipment during the phase of construction.

Steel pins shall be used for setting out or survey marks.

However, it is proposed also to establish stable benchmark points which are unlikely to move or be damaged from the time they are set to the time they are used to establish the elevation.

Examples of “stable” reference points are a chiseled cross in concrete or an outcrop, an anchor bolt set into concrete, a nail driven in a tree trunk, stable rebar driven in a location that will survive construction, as well as others.

Establishment of Temporary Bench Marks
The contractor will commence the survey from the determined and approved control points of bench mark related to QNHD provided by the 3rd party which have an appropriate order of accuracy in order to carry out the topographical survey.

The contractor will establish benchmarks at the suitable density and for spacing for the purpose of survey and work. This initial set up of benchmark shall be checked by the surveyor to confirm their correctness and accuracy and will provide 3 benchmarks for each working area as required.

The key benchmarks will be protected from potential damages during construction activities caused by work, by means of barriers e.g. steel barricade/enclosures, barricade tapes to prevent encroachment and disturbance.

Using Total Station equipment, coordinates/positions of the benchmarks will be taken and recorded.

Where this equipment is used, a minimum of 3 sets of observations/measurements shall be taken at each established by closed traverse set up. Where possible, the length of sight (Back sight marks and Foresight marks) shall be of similar distance.

The contractor shall height all-new benchmarks using spirit leveling equipment for the following application:
The maximum distance between level and leveling staff shall not exceed 50 meters.

The length of sight (backsight and foresight) shall be approximately equidistant to within ± 5 meters.
The maximum center-wire reading shall not exceed 2 meters on the staff.

All survey instruments to be used during the entire duration of project execution shall be accurately and carefully maintained that is, preventive maintenance and calibration schedule shall be properly and strictly observed.
The regular checking intervals of the established TMB will be done connecting to no less than two other approved control stations.

TBM’s should be checked on a quarterly basis.

Survey Reports of Quarterly Controls shall be submitted after completion of survey activity.

The location of temporary benchmarks shall be agreed upon with the consultant. The level of temporary benchmarks shall be related to the Qatar National Height Datum (QNHD). An existing benchmark or control station related to the Qatar National Height Datum will be indicated by the consultant for this purpose. The Contractor shall prepare a plan detailing the location of the benchmarks and temporary benchmarks and keep it up to date for the duration of the Contract.

The Contractor shall protect and maintain the temporary benchmarks until the project is complete. Upon completion, the Contractor shall clear away the temporary benchmarks to the satisfaction of the consultant.

The Contractor is responsible for checking the accuracy of the temporary benchmark. Any re-work resulting from incorrect or inaccurate temporary benchmarks shall be undertaken at the Contractor’s cost.

Site Grid/Zones
As may be required, the contractor shall implement a Project Site Grid-tied to the Qatar National Grid, oriented and labeled as specified by and agreed with the Consultant Engineer. The final survey grid shall be arbitrary but related to the National Grid (QND95). A description of the grid system used shall be quoted on each survey plan or upon the index plan.

Total Station
Total station shall be used to set-out locations, alignment, and plumpness of structures (foundations, columns, walls, slabs, steel frames, etc.) based on approved setting-out drawing coordinates and with reference to established TBMs.

This equipment shall also be employed to undertake a topographic survey and as-built survey as required.

Automatic Levels
Automatic levels shall be used for verifying the level control station, fixed new TBM levels, and finalize all required item levels on site.

Survey and Setting Out
The survey team firstly determines the location of project control points and datum (provided by others). Then they will check the relationship between these control points and datum’s and the setting out points and datum provided within the building (by others). Any discrepancy between these points shall be notified to the project team for agreement prior to proceeding with the setting out activities.

The survey team shall ensure that they work within the confines of the existing perimeter edge protection provided.

Setting out of foundations, steel frames, etc. is done through the coordinate method. All points must be marked and corresponding dimensions are checked with respect to the approved drawings.

Setting out of coordinates is issued only based on approved shop drawings.

The contractor shall establish the theoretical grid line positions at the ground floor of the building & this grid line shall be transferred to the other floors from existing horizontal control points the outside of the building.

The theoretical grid lines shall be marked around the perimeter of the floor slabs by grid lines offset identified using metal pins or chalk lines applied directly to the slab. ( for finishing job).

Level datum or slab level surveys shall be transferred to all floor levels (if applicable) and shall be marked as control datum 1 meter from SSL (Slab Surface Level).

The survey team shall verify the as-built position of the structure in relation to the theoretical grid lines and datum levels and shall immediately notify the project team of any discrepancy from the agreed tolerances. Any discrepancies shall be immediately highlighted and inform the project team for rectification.

All information relative to the as-built survey of the existing structure and cast-in items shall be recorded.

After completion of survey to a sufficient area setting out of the precast elements and structural frames installation shall be carried out. Setting out shall be completed on all structures and other elements basis which shall be completed generally by marking reference to the positions via grid lines with spray paint.

Controlling Precast Elements, In-situ Concrete, Formworks, and Blindings for Levels
The pre-cast system will be checked for levels, alignment, (which applies to both horizontal control and vertical position) and plumpness, once positioned.

The survey can be carried out from the foundation below or from the top level.

Standard level survey techniques will be used.

The concrete pouring of the cast-in-situ concrete slab, foundations, wall, columns, blindings, formworks, and other structures (i.e road networks) will be controlled using a leveling instrument possibly a laser level or conventional leveling method.

Control of the core wall
On-site, two separate methods will be used: there are formworks that will be 2,3 or every 5 levels above the current slab, while others will be on the slab and only rise to the next floor.

The laser plummets or the optical plummet will be used to layout control on the new slab and plumbed to the formwork platform. Once the slab has been cast all permanent grid points and grid lines shall be marked by the surveyor. Accuracy at all times shall be implemented.

These marks are then used to verify and set the shutter locations. While formwork is being moved up each level, the verticality of the lift core walls must be checked. However, every 5 floors, including two diagonally opposite corners of lift shafts, the frequency of results must be generated and logged.

The verticality of all shafts will be monitored from the external wall coordinate.

Control of edge of a slab
To monitor the edge of the slab, surveying of the points are laid out on the slab below each span and plumbed to the next level. After the slab has been cast, the surveyor shall mark all permanent grid lines.

Column, walls & shafts control
Four offset points or two lines are to be marked on the current slab defining the base of the column. This also applies to the walls, shafts, and other structural elements as applicable.
After casting and deshuttering lines of columns shall be rechecked.

Quality Assurance – Tolerances for Method Statement of Surveying Works

If during the general day survey work or as a result of an as-built survey it is found that a particular element does not conform to the positional tolerances nominated the surveyors will immediately notify both the project manager & the QA QC manager in the form of a nonconformance notice.

Record Keeping & As-Builts
Field observations and details will be kept in the survey field book.

‘As built’ sketches shall be kept in their designated folder

Calculation and worksheet will show the drawings and revision numbers of drawings used onsite.

As far as is practical only the drawings kept in the drawings office will be used as copies of the drawings. Surveyor’s responsibility is to make sure that the latest revision of drawings for set out is used on site.

In addition to the as-built survey file maintained in the survey office, the surveyors will maintain a similar file in the construction manager’s office.

The construction manager ought to an up-to-date reference of all as-built information at all times.

Communication
‘As built’ information needs to be communicated to the project manager, construction manager, and relevant foreman for perusal.

Copies will be forwarded to the document controller for external distribution.

Any unusual results or results exceeding the specifications will be highlighted and the project manager informed. This will be communicated to the Consultant Engineer in the form of an RFI (Request For Information) for further disposition.

Particular Survey Inspection Request (IR) will be submitted to Consultant Engineer for all relative activities that require prior survey setting out, levels, elevations, horizontal and vertical position survey control determination following the subsequent construction activities.

Attach with the Survey Inspection Request (IR) is the usual complimentary form of Survey Report.

All survey data is stored in the data card onboard the instrument and transfers to and from the computer. These data can be retrieved and viewed in two formats:
DXF format for .dwg files (Autocad files)
CSV format for .xls files
Wherein either DXF & CSV formats will be shared to Consultant Engineer /Surveyor along with the related Survey Inspection Request (IR).
Drawings are sent by email in pdf and AutoCAD dxf or dwg format.

Responsibilities/Supervision

Project Manager
The Project Manager is responsible for managing the Construction activities and provide general interface between Sub-contractors.
Monitor progress and site resources.
Review of the construction methodologies and ensuring the construction team and subcontractors abide with agreed methodologies.
Implement agreed quality procedures and ensure the Construction Inspection / Supervision Team understands the requirements.

Site Engineer
Liaising with clients and their representatives (engineers and surveyors), including attending regular meetings to keep them informed of site progress.
Issuing daily reports.
Day-to-day job supervision of the site, including supervising and monitoring the site labor force and the work of any subcontractors.
Planning the work and efficiently organizing the plant and site facilities in order to meet agreed deadlines

QA/QC Manager
To support QC Engineer with the necessary information and remarks
To coordinate with the QC Engineer in reviewing all relevant documentation and testing activities.
To be in direct contact with Project Managers and Construction Managers to obtain and/ or provide necessary information pertaining to inspection and/ or testing.
Responsible in providing all information including shop drawings required for the work.
Responsible for the works carried out are as per the plan agreed with the engineer and the consultant.
Maintain all documentations required and ensure correct information is given to all concern.
Ensure that quality inspections are regularly performed at site in accordance to specification and standards.

QA/QC Engineer
The QA/QC Engineer is responsible to ensure work has been executed on field as per the specification and approved method statement for surveying.
He is responsible for quality inspection as per method statement for surveying.

Safety and Health Manager
The Safety and Health Manager is responsible to ensure that all safety precautions and procedures are in place.
He may conduct audits or inspections to ensure said compliance.

Safety and Health Officer
The Safety and Health officer is responsible for monitoring and ensuring that all safety precautions are being followed by the respective engineers, supervisory staff, In addition ensure that the supervisory staff have confirmed checked that all personnel have undergone any necessary induction trainings and that all personnel are equipped with (PPE) Personal Protective Equipment.
The Safety officer shall ensure that all works have undergone the necessary pre-commencement STARRT talk provided by the works supervisor.
The Safety officer shall periodically inspect all works ensuring adequate signage and permits are in place.
The Safety officer shall conduct inspections as and where necessary to ensure plant equipment is in full compliance with the projects requirements. Where deemed appropriate issue corrective action notices and or observation reports in line with procedures.

Chief Surveyor
Supervises the survey team daily activities on site.
Ensures that surveying data are collected and recorded accurately including shape, contour location, elevation and dimension of land features.
Ensures that the survey team follows company standards and procedures for operations and safety.
Leads the survey team making sure that the work on site is accurate.
Leads and participates in a variety of land survey operations such as boundary, topography, leveling, design, as-built, and maintaining horizontal and vertical control networks utilizing a full range of survey equipment.

Project Surveyor
Leads the Land surveyors during setting out and controlling the quality of site setting out.
Prepare survey reports and maintain records.
Supervise the land surveyor for the use of equipment, preparation of sketches and notes and electronic data collection.
Prepare reports on Surveyor’s performance.
Prepare all the necessary data (Points x, y & z value) for the Surveyor on Site.
Double checking on the orientation of the drawing received by the
Technical Department prior to start data preparation.

Survey Helper/Aide
Maintain and use Surveying equipment. Assist surveyors in taking measurements, record measurements manually or electronically, and peg out boundaries.

Manpower Requirement

Chief Surveyor
Project Surveyor
Survey Helper/Aide
Draughtsman for production of as-built drawings (As required)
Safety Officers
Site Engineer

Equipment Requirement

A combination of modem, both electronic and conventional, survey equipment should be used to achieve required survey accuracy. The list of survey equipment includes (but is not limited to):

Total Stations (LEICA TS15 or the like)

Total Station Equipment

An electronic/optical theodolite integrated with an electronic distance meter to read distances from the instrument to a particular point. Provides high accuracy angle measurements and precise long-range distance measurements backed by automatic fine pointing and fast, reliable reflector location.

Instruments will allow for internal data storage and the measurement of horizontal and vertical position angles.
Total Station instruments will be returned to the manufacturer every 6 months for testing and calibration.

Auto levels (NIKON Automatic levels)

Level instruments will be returned to the manufacturer every 6 months for testing and calibration. In addition, an opposite two peg will be performed periodically or before major datum transfers.

The survey team will also use a range of equipment including range poles, stadia rods, steel bands, tape measures, bar levels, etc.
Rotating laser leveling equipment (Optional)
Laser levels (Optional)
Laser Plummets (Optional)
Measuring Tapes, Marker, Chalk, Spray Paint
Other general surveying and setting out equipment.

Accuracies

The following are based on the manufacturer’s specifications
LEICA TS15 Total Station
Auto levels (NIKON Automatic levels)

Data Transfer and Processing of Data

All survey data is stored in the data card onboard the instrument and transfers to and from the computer.
These data can be retrieved and viewed in two formats:
DXF format for .dwg files (from Autocad)
CSV format for .xls files

Drawings shall be delivered by email in pdf and dxf or dwg autocad format.

Survey Equipment Maintenance Schedules

All survey equipment is to be checked for accuracy at least once a month. Chief Surveyor is responsible for maintaining up-to-date records of survey equipment and calibration certificates.

Maintenance guidelines:

Auto levels to be checked for collimation error on weekly basis and adjusted if necessary by Chief Surveyor.
Total stations calibrated by authorized ISO certified dealer. Horizontal and vertical collimation on each piece of equipment should be calibrated as well.

Other Equipment and Consumable Materials

The Surveying Team shall use the following consumable materials:
Plates and pins will be used for marking of datum and setting out positions.
Paint for inscribing permanent grid lines and datum.
Chalk line/powder for marking of permanent grid lines, columns, walls, boundaries, etc.

Health, Safety & Environment

The health and safety activities are to be in accordance with the relevant Health, Safety and Environmental requirements as described, but not limited to, within the guidelines for method statement.

The contractor shall ensure that the Health and Safety Management Plan is followed stringently.Where applicable particular site safety procedures shall be adhered to at all times during site works.

All site workers and staffs to attend safety inductions.

A Daily tool box talk shall be given to all employees; this shall include a 360 Haz ID (STARRT), findings of which shall be discussed and where practical mitigated.

All workers shall hold in their possession of identification ID cards along with training ID Cards.
In the event of an emergency the Site Engineer shall immediately inform the the Health, Safety & Environment (HSE) Manager providing them with all relevant information regarding the emergency.

During the works, contractor shall ensure adequate barricading in order to restrict access to authorized personnel only.

Ensure that the personnel deployed are trained and competent to perform the specific task, under the supervision of competent supervisors.

Ensure all workers comply with the requirements of summer working hours.

Keep available, records of hazards on particular sites. Make sure all relevant people are notified.

Helmets, steel capped high angle shoes, safety goggles, high visibility jackets, face masks, overalls should be appropriate and in good condition

QC Approval and Other Document Requirements

Follow approved Method Statement for Surveying, Project Quality Plan, Health and Safety Plan (HSE) Plan & Checklist.

Supporting Documents

This method statement for survey works to be read in conjunction with the below-referenced documents:
Contract Specification
Approved shop drawings
Project Quality Plan
Project HSE Plan

Distribution of the Approved Copy of Method Statement for Surveying Works

Copies of this method statement for surveying will be circulated to the following for information & action
Project Manager
Project Engineer
Chief Surveyor
Project Surveyor
Site Engineer
QA/QC Engineer
HSE Engineer
The contractor must have access to a copy of the work method statement when on site and be able to provide it upon request.

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