Winchester

Do you cover Winchester and the surrounding towns, and is there a local office?

Yes, we cover them. We attend sites across Winchester and the villages around it, from Kings Worthy and Alresford to Twyford, Colden Common and Chandler’s Ford, and along the M3 and A34 to Eastleigh, Southampton, Andover and Basingstoke. Beyond that the same number covers the rest of Hampshire, Dorset and the Sussex coast: Portsmouth, Bournemouth and Poole, the New Forest, the Isle of Wight and east along the coast to Hastings. There is no Hixtra office in Winchester or anywhere in the region. The 01962 number rings through to the laboratory in Milton Keynes and every team travels from there. Coverage means we attend; it does not mean staff, vehicles or kit are kept locally. Soil and aggregate samples travel back to the laboratory with the team, or you can courier them.

Which tests can you carry out on a Winchester site?

On chalk the usual requests are plate bearing testing on formations, capping and working platforms, and in-situ CBR testing on estate and highway road formations, with DCP testing where flints allow it. LWD testing is a quick way to check a compacted capping layer across a large area, and on the sands towards the coast density and compaction testing matter as much as CBR. We take soil and aggregate samples and cut concrete cores on the same visit. The laboratory in Milton Keynes runs soaked laboratory CBR, classification, compaction, chalk, chemical and aggregate tests, and concrete cube compressive strength testing on cubes made on your site. Fresh concrete testing at the pour does not reach Winchester. The full range is on the testing services page.

How quickly can you attend a site in Winchester, and how is Isle of Wight work scheduled?

Same-day and next-day dates are often available, subject to the schedule. We never guarantee an attendance time, but the south coast is a reasonable run from Milton Keynes, so dates are usually easier to find here than in the far south west or the north. The Isle of Wight is the exception. Ferry crossings have to be built into the day, so island work is planned rather than squeezed in and a same-day date there is unlikely. Give us the positions, the rig or crane loads and a preferred window and we will book the crossing around them. If you have positions on both sides of the Solent, say so and we will try to sequence them.

Why does the timing of a plate bearing or CBR test on chalk matter so much?

Because chalk only gives its good result while it is intact. The Chalk of the Hampshire Downs, the South Downs and the Isle of Wight is stiff and strong undisturbed, with high plate bearing stiffness. It is also very sensitive to remoulding. Worked wet, or run over repeatedly by dumpers and excavators, it degrades to putty chalk and the formation is lost; the plate settles far more and the CBR falls away. The test reports the state of the chalk on the day, so a formation trafficked for a week in rain will fail a specification it would have passed the day it was cut. Test soon after exposure, keep plant off the formation, protect it, and tell us the history when you book.

What do flint bands and Clay-with-Flints do to CBR and DCP results?

Flint bands run through the chalk and distort any test that pushes a small point into the ground. An in situ CBR plunger that lands on a flint reads far too high; a DCP cone on a flint gives a refusal that looks like a strong layer. Neither is the strength of the chalk. We log these, move the position and report what happened, rather than pass off a flint as ground strength. Clay-with-Flints caps much of the downland and varies in thickness and behaviour. A scheme on the tops can move from clay to chalk and back within a few hundred metres, so read the ground investigation and expect them to test differently. A plate bearing test is less affected by isolated flints than a CBR.

What is the ground like around Bournemouth, the New Forest and the Solent?

Different from the chalk a few miles north. Bournemouth and the New Forest sit largely on sands and gravels of the Poole and Branksome formations, which drain well and give consistent CBR and plate results when the moisture is controlled. Specifications on these sands are usually about density and compaction as much as bearing, so density testing often sits alongside the CBR. The Hampshire Basin around Southampton, Portsmouth and the Solent is more complicated: London Clay, the Bracklesham and Barton beds and the Bagshot Sands alternate over short distances, so a position on sand and a position on clay on the same site can give very different values. Alluvium in the coastal harbours is soft and compressible and needs treating as a separate case again.

What should I know about testing around Hastings and the Weald?

East Sussex around Hastings sits on the Hastings Beds and Weald Clay, alternating sands and clays that change over short distances, so a single test rarely characterises a site and positions need spreading across the scheme. The clays are moisture sensitive in the way any high plasticity clay is, and the sands can lose strength when wet. The coast here has well known landslip, and any crane pad, working platform or haul road near the cliff line needs the geotechnical consultant’s stability assessment before it is designed; a plate test proves the platform, it does not prove the slope beneath it. Tell us if a position is close to the coast so we can plan the reaction machine’s approach and where it can stand safely.

Plate bearing, CBR, LWD or DCP: which should I ask for on chalk and sand?

Follow the specification first, then think about the ground. On an intact chalk formation a plate bearing test is the most reliable measure and it is what platform designers ask for; an in situ CBR on chalk is possible but flints and remoulding make it more scattered. For estate and highway road subgrades the specification will usually ask for CBR, and on Clay-with-Flints or the Solent clays a laboratory soaked CBR on a sample is often the value that governs. LWD is quick for checking uniformity across a granular capping over chalk, but it is not a plate test and designers will not accept it as one. DCP is useful on the sands and on alluvium to profile strength with depth; on flinty chalk it refuses and misleads.

Which standard is plate bearing testing usually carried out to?

Plate bearing tests are usually carried out to the plate loading method described in BS 1377-9, with the plate size, load increments and maximum applied pressure set by your specification. Tell us what the result has to demonstrate and we will confirm the method before booking.

Can you do fresh concrete testing in Winchester or elsewhere in Hampshire?

No. Fresh concrete testing, meaning slump, flow and cube making at the pour, is only offered within about an hour’s drive of Milton Keynes, and that does not reach this region. Basingstoke is the closest of the towns on this page and is still beyond it on most days, so ask rather than assume; Winchester, the coast and the Isle of Wight are well outside. For pours here you will need a technician nearer to hand for the slump and the cube making. Hardened concrete is different: cubes made and cured on site can be sent to the laboratory in Milton Keynes for testing, and coring is a site visit we make anywhere in the region, island included.

Do you test hardened concrete cubes and cores from sites in this region?

Yes, throughout Hampshire, Dorset, Sussex and the Isle of Wight. The fresh concrete radius does not apply to hardened concrete. Cubes made by your team or your readymix supplier can be delivered to Milton Keynes for crushing at the ages the specification calls for, usually 7 and 28 days, with the density and failure type recorded on the report. Coring is a site visit: we cut cores from slabs, hardstandings, quay aprons and pile caps where cube results are missing or disputed, or where a designer wants the in place strength before loading. Cores go back to the laboratory for preparation and testing. If accreditation matters, ask which concrete methods are on the UKAS schedule before you book.

Do you test working platforms for piling rigs here?

Yes. Platforms in this region are usually a granular layer over chalk, over the Solent clays or over alluvium in the harbours, and each behaves differently under a rig. On chalk the platform designer often relies on the chalk itself, so the state of the formation when the platform was built matters as much as the stone on top. On alluvium the platform does the work and the subgrade strength from the ground investigation drives the design. We plate test at the positions the rig will track and stand on and report the values needed for the check, normally to the approach in BRE 470. Send the rig type, its bearing pressures and a plan of the positions with the enquiry.

Can you test crane pads for port, marine and coastal work at Portsmouth, Southampton and Poole?

Yes, and it is a regular part of the work here. Port and marine crane positions are often on reclaimed ground or alluvium behind a quay, sometimes on made ground over old dock fill, with high outrigger loads and limited standing room between the water and the live operation. We plate test each outrigger position to the bearing pressure in the lift plan and report the settlement and allowable pressure at each. A plate stresses a shallower depth than a large outrigger mat, so on soft alluvium the plate can pass while the mat loads softer ground beneath; where that is a risk we say so and a DCP at the position helps. Port sites usually need inductions and escorts, so tell us the permit process early.

Is the testing UKAS accredited?

Hixtra holds UKAS accreditation to ISO/IEC 17025 under schedule number 8996. Accreditation is granted method by method, not to the company as a whole, and it covers only the tests on the current schedule. Most of the soil and aggregate tests we run, which make up most of the chalk, sand and clay work in this region, are on it. Some concrete tests are still going through the process. So some of what we do is accredited and some is not, and it depends on the method, never on the company. If a specification for a highway scheme or a port client calls for a UKAS accredited result, name the test when you enquire and we will confirm whether that method is on the schedule before you book.

What do you need before you come out, and how do results arrive?

The site postcode and a gate location, then the specification: plate size, target bearing pressure or settlement limit, target CBR, and crane or rig loads if the test is for a platform. On chalk, tell us when the formation was exposed, whether it has rained since and what has trafficked it. Then the number of positions and a marked plan, access for the reaction machine, working hours and any induction or permit requirements, which matter at the ports. For the Isle of Wight, tell us which ferry route suits the site. Site results are normally reported the same day as a PDF with positions, load increments, settlement readings and derived values. Laboratory results follow when the test finishes.