A F Howland Associates

A F Howland Associates

26 services found

Services

  • Site Investigation

  • Cable Percussion Boring

    Cable Percussion Boring

    Light-cable percussion is the most common drilling method used for geotechnical site or ground investigations. Depending upon access limitations and favourable ground conditions deep boreholes up to 50m depth can be formed. Light-cable percussion drilling uses a mobile rig with a winch of between one to two tonne capacity driven by a diesel engine and a tripod derrick of about 7m height. The derrick folds down so that the rig can be towed by a...

  • Dynamic Cone Penetrometer (DCP) Test

    Dynamic Cone Penetrometer (DCP) Test

    The California Bearing Ratio (CBR) test is a penetration test developed by the California State Highway Department and is used to determine the mechanical strength of a soil. The test can be carried out on site or in the laboratory. The VBR test is carried out using a cylindrical plunger which penetrates the soil at a given rate. The relationship between the force and penetration can then be used to calculate the CBR value of the soil being tested.

  • Dynamic Probing

    Dynamic Probing

    Dynamic probing involves driving a cylindrical sacrificial or fixed cone into the ground using a high frequency percussive hammer. The diameter and angle of the cone will depend upon the chosen method. For example the heavy or super heavy dynamic probe has an angle of 90 degrees. The cone is attached to a 1m section steel rod with a nominal diameter of approximately 35mm and graduation markings set at 100mm intervals. Depending upon the chosen method,...

  • Rotary Core Drilling

    Rotary Core Drilling

    The rotary drilling technique is normally used for forming a deep observation borehole or for obtaining representative samples of rock which could not be recovered using conventional light cable percussion drilling methods. Powered rotary cutting tools use a cutter head on the end of a shaft, which is driven into the ground as it rotates. The system requires lubrication (air, water or drilling mud) to keep the cutting head cool and remove the soil or...

  • Trial Pit Excavations

    Trial Pit Excavations

    This technique is normally used for recovering near surface large bulk samples of granular soil or if close visual examination of the strata is required. The main advantage of this method when compared to percussion drilling is the relative speed with which the work can be carried out. The disadvantage is the level of surface disturbance suffered and the difficulty in carrying out the effective reinstatement of the excavations. Trial pits can be...

  • Plate Loading Test

    Plate Loading Test

    Plate load tests are used to make a determination of the vertical deformation and strength characteristics of soil and can allow an estimate of ultimate bearing capacity, shear strength and modulus of sub-grade reaction to be made. The method involves applying a load through a rigid plate and assessing the amount of penetration with time. The test may be carried out at ground surface or in shallow pits and trenches. Common uses are to assess the...

  • Window and Windowless Sampling

    Window and Windowless Sampling

    Percussive window or windowless sampling involves driving cylindrical steel tubes into the ground using a high frequency percussive hammer. Usually the hammer is driven by a hydraulic power pack, but electric and pneumatic hammers are also available to suit particular site conditions. The drilling rig is normally track or crawler mounted and some of the rigs are small enough to be driven through a conventional sized door way. However, in areas where...

  • Geotechnical Services

  • Geotechnical Design

    Geotechnical Design

    Geotechnical Design applies the fundamentals of soil and rock mechanics to civil engineering design and construction.  AFHA provide a bespoke, site specific service when assessing the geotechnical requirements of proposed developments.Every ground investigation is site specific and tailored to meet the engineering requirements of each project.The scope of works of the investigation will depend upon the anticipated ground conditions and the...

  • Subsidence Investigations and Analysis

    Subsidence Investigations and Analysis

    Subsidence is a major cause of failure of structures due to excessive settlement of foundations. There can be a multitude of causal factors including: Instability due to the presence of naturally occurring voids or unmapped mine shafts or workings, Settlement and compaction of soils due to percolation of water, Groundwater level fluctuations, Variation in the moisture content of clay soils

  • Litigation & Expert Advice

    Litigation & Expert Advice

    A F Howland Associates' experience in litigation includes formulating the contractual conditions and specification for term contracts for site investigations such as the London Docklands Development Scheme. We engineered the innovative approach to provide a specific term contract for chemical/environmental investigations as well as one for traditional geotechnical investigations, which is believed to be the first of its kind.

  • Contract Research & Development

    Contract Research & Development

    A F Howland Associates provide a research and development service whereby we are contracted to assess and evaluate construction processes, describe the basic mechanics and develop guidelines for the use of our clients for their respective projects. We have developed design guidelines for the construction process of soil nailing for use in flood defence systmes for clients sich as the Environment Agency. As part of this service we also described the...

  • Thermal Resistivity

    Thermal Resistivity

    The thermal resistivity of soils can be measured in the field in trial pits or boreholes or under laboratory conditions.  The results provide data to determine the thermal insulating properties of a soil.  A F Howland Associates can collect and provide the raw data needed to derive cable ratings for underground cable routes.  Laboratory measurements can be carried out on undisturbed soil samples or re-compacted soils.  Compaction...

  • Electrical Resistivity

    Electrical Resistivity

    Electrical resistivity of soil or rock can be measured using. Electrical resistivity testing can be performed on soils or rock to provide corrosivity values of for accurate selection of appropriate pipeline materials. A F Howland Associates can carry out this testing in the field or in the laboratory on undisturbed or disturbed samples.

  • Phase Three – Remediation and Validation

    Phase Three – Remediation and Validation

    If significant levels of contamination are identified by the Phase One and Two investigations, developments do not necessarily stop. A site specific Remediation Method Statement can be designed, which, subject to LPA approval, can allow development to proceed. Methods of remedial works can include the following: Excavation and replacement, Strategic emplacement of hard cover, Utilising ground gas ingress prevention techniques, Pump and...

  • Environmental Services

  • Pre-Purchase Evaluations and Summary Site Investigations

    Pre-Purchase Evaluations and Summary Site Investigations

    A F Howland Associates can undertake pre-purchase reviews to determine the probable scope of works required for the site.  Where site investigations have already been carried out by the vendor AFHA can also review the quality and applicability of the reports and provide advice where necessary. Summary site investigations of undeveloped sites in order to assess the future costings of proposed works can also be undertaken.

  • Phase One – Desk Study and Walkover Survey

    Phase One – Desk Study and Walkover Survey

    A F Howland Associates recommend that a Phase One desk study and walkover survey is carried out prior to development of any site. This consists of a review of existing geological and hydrological mapping, register searches, past editions of Ordnance Survey maps and other information systems, including Local Authority and Environment Agency records, fully supported by any anecdotal evidence. Potential hazards from ground instability, landfill...

  • Phase Two – Intrusive Investigation

    Phase Two – Intrusive Investigation

    A Phase Two Investigation is required if potential contamination is identified by the Phase One survey. This includes a detailed site investigation to determine the nature, extent and degree of contamination, the scope of which must be agreed with the LPA before commencement of works. A Phase Two contaminated land survey typically requires invasive/intrusive investigation by way of exploratory holes, sampling of soils, chemical laboratory testing and...

  • Flood Risk Assessment

    Flood Risk Assessment

    Flood Risk Assessments (FRAs) are sometimes required as part of the planning process where the proposed development site is deemed to be susceptible to flooding by the authorities. The FRAs are prepared in accordance with Planning Policy Statement 25 “Development and Flood Risk” (PPS25). It incorporates (i) an assessment of the potential to increase flood risk elsewhere, through the addition of hard surfaces and (ii) the effect of the new...

  • Planning Application Advice

    Planning Application Advice

    Bespoke Solutions for Discharging Specific Conditions or Objections. Not all contamination problems are easily solved through phased site investigation and risk assessment procedures. Beskpoke investigations can be designed to address specific conditions or objections to planning applications by the Local Authority. A F Howland Associates can also act in an advisory capacity to stakeholders for mediation regarding environmental matters with regulators...

  • Environmental Monitoring

  • Acoustic Surveys

    Acoustic Surveys

    Acoustic surveys also have a variety of applications but are typically used to ensure that specified maximum decibel levels of newly installed machinery are not exceed upon completion of installation. These are usually required so that health and safety regulations are complied with.

  • Groundwater Sampling – Traditional or Low Flow Sampling

    Groundwater Sampling – Traditional or Low Flow Sampling

    While fixed-volume purging with bailers or submersible high-flow pumps can remove overlying stagnant water from a well and provide a sample of the groundwater near the borehole, researchers have determined that these traditional purging practices pose significant scientific and practical concerns.

  • Ground Gas and Volatile Organic Compound (VOC) Monitoring

    Ground Gas and Volatile Organic Compound (VOC) Monitoring

    A F Howland Associates undertake ground gas investigations in accordance with CIRIA C665 and NHBC recommendations. We utilise fully calibrated MiniRAE 2000 photo-ionisation detector (PID) for VOC monitoring and Geotechnical Instruments GA2000 for ground gas monitoring.  The GA2000 records oxygen, carbon monoxide, carbon dioxide, hydrogen sulphide and methane in addition to flow via a separate flow pod attachment.  The PID is best applied for...

  • Inclinometer Monitoring

    Inclinometer Monitoring

    The purpose of inclinometer monitoring is to observe lateral movements within structures or strata and assess whether remedial works are required to subdue any such movements. AFHA undertake inclinometer monitoring using a technique designed to be used within standpipe casings inserted in boreholes.  An inclinometer probe is used to take measurements of lateral earth movements such as might occur in instable slopes, dam and roadway embankments or...

  • Thermographic Surveys

    Thermographic Surveys

    Thermographic surveys utilising the latest in thermal imaging technology can be carried out where preventative maintenance is required.  These surveys have typically been applied to electricity substations but the basis of the survey has many applications.

  • Environmental Monitoring of Hydrocarbon Contaminated Groundwater

    Environmental Monitoring of Hydrocarbon Contaminated Groundwater

    A F Howland Associates has experience in investigation of sites contaminated with hydrocarbon products, specifically NAPLs (Non-Aqueous Phase Liquids) primarily of heating oil composition. Where contamination is suspected, exploratory holes are carried out to confirm of disprove its presence and standpipes are installed to allow in-situ sampling and monitoring of groundwater. An oil/water interface probe is used to determine thicknesses of NAPL...

  • Vibration Monitoring

    Vibration Monitoring

    A.F. Howland Associates are now please to offer vibration monitoring as one of our core services. Vibration monitoring is a useful tool in mitigating the risk of damage to structures due to activities that are known to produce ground borne vibrations.