4 Information needed for the execution of the works
4.1.1 Prior to the execution of the work, all necessary information and site investigation data shall be available.
4.1.2 This information should include:
- a) any legal or statutory restrictions;
- b) the location of main grid lines for setting out;
- c) the conditions of structures, roads, services, etc.:
- 1) adjacent to the work, including any necessary surveys;
- d) a suitable quality management system, including super vision, monitoring and testing.
4.1.3 The information regarding the site conditions shall cover where relevant:
- a) the geometry of the site (boundary conditions, topography, access, slopes, headroom restrictions ...);
- b) the existing underground structures, underground and arial services, obstructions, known contaminations and archeological constraints;
- c) the environmental restrictions, including noise, vibration, pollution;
- d) the future or ongoing construction activities such as dewatering, tunnelling, deep excavations.
4.2 Special features for micropiles:
4.2.1 The following additional site informations shall be made available in the project documentation and be on site before commencement of the micropile works, where applicable:
- working platform levels;
- location of site datum;
- chemical aggressiveness of ground and/or groundwater (= exposure class according to EN 206–1);
- climatic conditions;
- possibility of stray electric current;
- potential instability of the ground;
- presence of existing piles, anchors, and/or other artificial obstructions in the ground (as for example wood, steel, etc. …).
4.2.2 The following items shall be investigated during design and shall be made available for execution where relevant:
- all necessary or relevant information for the production of the working drawings and method statements, where required;
- necessity, extent and procedure for any survey of the conditions of structures, roads, services, etc. adjacent to the works area. Where a survey is necessary it shall be carried out and be available prior to the commencement of the works;
- the allocation of design, execution and supervision activities and responsibilities of all the parties involved.
They shall be clearly specified in the project specifications;
- previous experience with micropiles or other foundations or underground works on or adjacent to the site;
- acceptable deformation of adjacent structures;
- dimensions and composition of existing foundations and floors;
- condition, stability and acceptable deformation of structures to be underpinned;
- existing drainage and groundwaterlowering systems.
4.3 List of activities
Design and execution should include, as appropriate, the following activities:
NOTE The order shown does not necessarily represent a time sequence.
- a) assessment of the design assumptions with respect to the site investigation data and construction feasibility;
- b) execution of preliminary or trial micropiles if required and of the tests on these micropiles;
- c) evaluation of the results obtained from preliminary and/or trial micropiles; d) definition of the construction sequence of a micropile taking account of c); e) directives regarding the construction sequence if required;
- f) instruction to all parties involved of key items in the design criteria to which special attention should be directed;
- g) specifications for monitoring the effects of micropile construction on underpinned and/or adjacent structures (type and accuracy of instruments, frequency of measurement) and for interpreting the results;
- h) definition of tolerable limits regarding the influence of micropile installation works on underpinned and/or adjacent structures;
- i) provision of construction drawings;
- j) specifications for control tests during execution and for micropile tests.