10 October, 2026 | 
Admin
Crane Hire and Outrigger Pads
Planning a crane lift in Qatar means solvi
Read moreCrane Outriggers on Sabkha and Reclaimed Ground in Saudi Arabia
09 October, 2026 | Admin
Short answer: sabkha is a salt-crusted coastal or inland flat that looks firm on the surface but is often weak and moisture-sensitive underneath. Published studies report low bearing capacity for Saudi sabkha, so crane outriggers on sabkha need much larger pads, conservative assumptions and, for any significant lift, site-specific geotechnical data. This guide explains how to plan sabkha crane outrigger pads on Eastern Province and Red Sea coast sites.
What Is Sabkha?
Sabkha (also spelled sebkha) is a flat, salt-encrusted surface formed where shallow saline groundwater evaporates. It is common along the Arabian Gulf coast around Dammam, Al Khobar, Jubail and Ras Tanura, around Al-Qurayyah, inland in parts of the Eastern Province, and along stretches of the Red Sea coast. Reclaimed land along the coast often behaves in a similar way, because it is built from dredged or placed fill over soft natural ground.
From a lifting point of view, sabkha has three problems:
- The crust is deceptive. A dry salt crust can feel hard underfoot and even support a vehicle, while the soil below is loose or soft.
- It weakens when wet. Salts dissolve when water is added from rain, tides, dewatering or a leaking line, and strength can drop quickly.
- It is variable. Strength can change across a single site and with the seasons, as the water table rises and falls.
What Do Published Studies Say About Sabkha Bearing Capacity?
Several studies give an idea of how weak sabkha can be. These are context only, not design values:
- A 2023 numerical (finite element) study of shallow foundations on salt-encrusted flat sabkha, published through Oregon State University and listed in the Saudi Digital Library, reported that the bearing capacity of sabkha soil was generally low, ranging from about 70 to 110 kPa depending on salt content and soil properties. It also found coastal sabkha weaker than inland sabkha. (source)
- A 2024 field study at a gas complex in the Eastern Province (Abas and Medawi, Journal of Umm Al-Qura University for Engineering and Architecture) reported that geotechnical testing found the bearing capacity of the native soil at that site, about 4 m of silty sand over weak sabkha, to be between 85 and 145 kPa. Ground improvement with stone columns was needed to reach the 200 kPa design target. (source)
- A 2016 review of Saudi sabkha (Arifuzzaman et al., Jurnal Teknologi) describes sabkha soils as well known for low bearing capacity in natural conditions, with very low CBR values before treatment. (source)
Neither of the two figures above is labelled as an allowable design value, and both apply to specific conditions. They show the scale of the problem: sabkha can be in the same range as, or weaker than, the 75 kPa “soft or reclaimed” planning value we use in our sizing guides. Always use your project’s geotechnical report for the actual lift.
Why Outrigger Pads Matter So Much on Sabkha
An outrigger float on its own puts very high pressure on the ground. Spreading the same load over a larger pad reduces the pressure in direct proportion to the area. On sabkha, where the allowable pressure is low, the pad area needed can be several times larger than on compacted fill. See our guide to ground bearing pressure for cranes for the formula.
| Leg load | Allowable ground pressure | Safety factor | Minimum pad area |
|---|---|---|---|
| 15 t (147.2 kN) | 200 kPa (compacted fill) | 1.5 | 1.10 m² |
| 15 t (147.2 kN) | 120 kPa (sandy) | 1.5 | 1.84 m² |
| 15 t (147.2 kN) | 75 kPa (soft / reclaimed / sabkha planning value) | 1.5 | 2.94 m² |
On the weakest ground, the 15 t leg needs almost three times the pad area it would need on compacted fill. The largest standard SafeRig pad is 3000 × 1000 mm (3.00 m²). If your minimum area is above that, a single pad is not enough: use ground protection mats or crane mats, or have the ground improved or assessed by a geotechnical engineer.
Planning a Lift on Sabkha: Step by Step
- Get the geotechnical data. Ask for the site investigation report, plate load tests or a geotechnical engineer’s allowable bearing value for the crane location.
- Get the worst-case outrigger reaction. Use the crane manufacturer’s data for the planned radius and boom angle. See our crane outrigger load calculation guide.
- Use a higher safety factor. On uncertain or soft ground, 2.0 is more appropriate than 1.5.
- Size the pad. Minimum area = leg load (kN) × safety factor ÷ allowable pressure (kPa). Use our free Outrigger Pad Size Calculator to check standard SafeRig sizes.
- Consider mats or a platform. If the required area exceeds a single pad, design a crane mat or prepared working platform with an engineer.
- Control water. Keep dewatering discharge, wash-down water and leaks away from the outrigger positions. Re-check after rain.
- Monitor during the lift. Watch for settlement, cracking around the pad or tilting, and stop if anything changes.
Material Choice for Coastal and Sabkha Sites
Salt, moisture and heat on Gulf coast sites are hard on timber and steel. Timber absorbs saline water, rots and splits; steel plates corrode and are heavy to move on soft ground. UHMWPE pads do not absorb water, resist salt and most chemicals, and are light enough to reposition by hand or with small equipment. See outrigger pads vs timber cribbing, steel plate vs plastic outrigger pads and outrigger pads extreme heat.
Where We Supply on Sabkha and Reclaimed Ground
We supply SafeRig outrigger pads from Al Khobar to projects across the Eastern Province, including outrigger pads in Jubail and outrigger pads in Dammam, where coastal sabkha and reclaimed land are common. Every order is supplied with a Material Test Certificate. For the full selection process, read our guide on how to choose outrigger pads.
Related Guides
Frequently Asked Questions
Is sabkha safe for crane outriggers?
It can be, but only with properly sized pads or mats based on site-specific geotechnical data. Sabkha is often weak under a firm-looking crust and weakens further when wet.
What bearing capacity does sabkha have?
Published studies report low values, for example about 70–110 kPa in a 2023 numerical study and 85–145 kPa at one Eastern Province site. These are context only; use your project’s geotechnical report.
How big should outrigger pads be on sabkha?
Size them from the outrigger reaction and the allowable bearing pressure from your geotechnical data, with a safety factor of up to 2.0. The pad area is often several times larger than on compacted fill.
What if one pad is not big enough?
Use crane mats or ground protection mats to spread the load further, or have a working platform designed by an engineer.
Recent Posts
High Visibility Reduce Trip Hazards
See our range of high-visibility safety mats and markers designed to reduce trip hazards across your site.
Related Blogs
