MGF EXCAVATION SUPPORT SYSTEMS MGF EXCAVATION SUPPORT SYSTEMS: Excavation Safety / Temporary Works Presentation

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1 MGF EXCAVATION SUPPORT SYSTEMS MGF EXCAVATION SUPPORT SYSTEMS: Excavation Safety / Temporary Works Presentation

2 Our Team Today Joel Clarke Neil Jennings Sales Engineer Technical Sales

3 Who We Are A leading provider of Excavation Support Systems Established for over 30 years Operate Nationally from 10 locations Over 300 employees directly employed Innovation at the heart of our operations In-house manufacturing 4500 temporary works designs completed annually Leaders in digital engineering Our sole focus Excavation Safety Solutions Dedicated technical sales and after care teams

4 Aims and Objectives For the contractor to: Who We Are The importance of Excavation Safety and Temporary Works Understand what is required in order to complete a Temporary Works Design Request Form / how to complete a Verbal Soils Description Fully understand the TWD & Drawing Recognise the importance of site checks and end ensuring on-site conditions are consistent with those considered in the TWD

5 Why Excavation Support? Construction is one of the most dangerous industries in the UK Every year between 40 and 80 construction workers are killed on construction sites and 500 to 800 seriously injured In the last 5 years there were 11 fatalities in construction in the UK where there seemed to be groundworks / excavation going on at the time and involved in the incident Excavations are notoriously dangerous due to the unpredictable nature of the ground conditions and associated risks include ground movement, collapse or cave-in, as well as potential impacts on surrounding structures, works and the public Every year between 2 and 8 construction workers are killed in collapsing excavations and between 40 and 60 are seriously injured Most fatalities occur in and around excavations less than 2.4m deep when either little or no temporary shoring has been provided

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7 How MGF Can Help Our products help to: Protect workers entering the excavation Protect workers working around or near to the excavation Protect the public Protect surrounding structures including the ground surface Protect the ground surrounding the excavation from movement Ensure safe access and egress to the excavation

8 Shoring Solutions The following factors need to be considered when selecting excavation support equipment. This needs to be done prior to excavating. Type of excavation Excavation dimensions Strength of equipment Ground conditions Availability Environment Plant Capacity Surcharges Groundwater Cost / Productivity

9 Shoring Solutions

10 Our Core Fleet

11 Temporary Works Temporary works (TW) as defined in BS 5975 are an engineered solution used to Support or protect an existing structure or the permanent works during construction Support an item of plant or equipment Support an excavation Provide access Why do we need Temporary Works? Safeguard workers/public. Facilitate a Safe Working environment. Protect any Adjacent Structures.

12 MGF Requirements What do we (MGF) need from the contractor in order to complete a TWD? Full Site investigation report. At minimum a borehole, trial pit etc located in the exact area. Plan drawings. Long section drawings. Manhole Schedule. Information on any additional Loadings. (Roads, Buildings, Cranes, embankments etc). Information on Water courses that may be near by and could potentially effect the TWD.

13 Design Request Form (DRF)

14 Verbal Soils Description Form The CDM Regs 2015 place legal obligations on all parties to provide all relevant information to enable them to perform their function. The Customer should be aware of the increase in their level of risk when only limited soil information is available. In the absence of any ground investigation, MGF recommend a number of trial pits are to be carried out on site prior to the production of the TWD to determine the ground conditions expected on-site. A verbal soils description form must be completed by a person with the appropriate skills, knowledge, experience and training. This will be provided to MGF DSL and the TWD will be based on the ground conditions encountered in the trial pit and recorded on the VSD. Photos to accompany Verbal Soils Description Form where possible. If required, a representative from MGF can visit site to witness the trial pits and to assist in the completion of the verbal soils description form.

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16 Design Complexity Risk

17 Design Complexity Risk

18 Temporary Works Procedures For Approval to Construction

19 Safe Systems Of Work Documents

20 Animated Install Guide

21 Excavation Management Site Checks Compare actual conditions encountered on site are consistent with design including: Dimensions Ground conditions / groundwater Method of Installation Site traffic / mobile cranes Surrounding structures Depth of dig Toe-in of pile / sheet Frame type & position(s) Kit installed as drawing (where applicable)

22 Excavation Management Site Checks MGF have a team of technical sales representatives and engineers who can be contacted to provide advice or visit site if necessary Design amendments will be deemed urgent by the Design Team to ensure you are not held up onsite Not all design amendments require additional or different kit, Design Team will do very best to utilise existing kit providing it works by the TWD. IF CONDITIONS ON SITE DIFFER TO THOSE CONSIDERED WITHIN THE TWD, PLEASE CONTACT MGF IMMEDIATELY FOR ADVICE/RE-DESIGN.

23 Hazards The presence of groundwater has a great effect on frame and sheet pile loadings When groundwater is present, controlling the flow of this toward the excavation can be a governing factor in a design Loadings on an excavation change at different stages during the installation of the equipment Surrounding structures and plant add load to the excavation Excavations can effect surrounding structures Ground conditions can change over time Small changes to a design can make a big difference. As can be seen in the following

24 Design Examples - Comparison Example 1 4.0m Deep 2.5m x 2.5m sheet to sheet 0.5m Toe-in Firm Clay No Groundwater No Superimposed Loads FIRM CLAY 10.9 kn/m Load / Capacity 120% 100% 80% 60% 2.8 knm/m 25.0 kn/m 40% 20% 20.0 kn/m 2 0% Ex. 1 Top Frame Lower Frame Trench Sheet

25 Design Examples - Comparison Example 2 4.5m Deep 2.5m x 2.5m sheet to sheet 0.5m Toe-in Firm Clay No Groundwater No Superimposed Loads 3.4 kn/m FIRM CLAY 250% 200% 150% Load / Capacity 100% 16.3 knm/m 44.3 kn/m 50% 0% Ex. 1 Ex kn/m 2 Top Frame Lower Frame Trench Sheet

26 Design Examples - Comparison Example 3 4.5m Deep 2.5m x 2.5m sheet to sheet 0.5m Toe-in Dense Sand No Groundwater No Superimposed Loads DENSE SAND 0.9 kn/m 500% 450% 400% 350% 300% Load / Capacity 250% 200% 150% 33.6 knm/m 67.9 kn/m 100% 50% 25.8 kn/m 2 0% Ex. 1 Ex. 2 Ex. 3 Top Frame Lower Frame Trench Sheet

27 Design Examples - Comparison Load / Capacity Example 4 4.5m Deep 2.5m x 2.5m sheet to sheet 0.5m Toe-in Dense Sand Groundwater at 3.5m No Superimposed Loads 51.0 knm/m DENSE SAND -8.7 kn/m 88.7 kn/m 800% 700% 600% 500% 400% 300% 200% 100% 0% -100% 33.8 kn/m 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Top Frame Lower Frame Trench Sheet

28 Problems with Groundwater / Running Sand Running sand is the flow of sand into an excavation or void due to water pressure. What are the likely problems we could encounter in excavations with running sand? High loads on frames and sheet Water within the excavation Migration of sand particles into the excavation Piping / Boiling of the formation

29 Dealing with Groundwater What can we do to alleviate the problems? Dewater excavation Use interlocking sheets & corners Ground freezing

30 GRiPSHORE Introduction Video

31 Questions