19BE2026Q0005 - Question and Answer.pdf

Nbr. Q&As Q01 If excavation depth or unsuitable soil quantity differs from 1.5 m / 900 m3 after COR inspection, will unit rates be used for adjustment?

A01 Yes, please provide the unit rate per substrate in your proposal for review. As mentioned in your question, any change must be approved by the COR.

Q02 Are there technical specifications or drawings beyond Attachment 2? If not, is the Contractor expected to propose the waterproofing system and construction details?

A02 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices Q03 Please provide existing drawings of the tunnel roof slab: top-of-slab level, cover depth, existing waterproofing system and its condition.

A03 Unfortunately, these drawings are not available at this time due to the proximity to critical public infrastructure. Drawings can be requested from the rail company after award. We have attached the information received from Infrabel thus far, including images and inspection information. Specifically see Attachment 5 - Drawings of the tunnel roof slab.

Additionally, a conditions plan is also included in Attachment 6 - Overview Drawing.

Q04 Is the new membrane to be applied directly on the tunnel roof slab, or at the base of the new pavement build-up?

A04 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices

Q05 Please specify the required waterproofing system type, thickness, and any preferred manufacturer or standard.

A05 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices

Q06 Please confirm the required thickness for the crushed stone base and both asphalt layers.

A06 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices

Q07 Please describe the drainage pipes to be replaced (diameter, material, length).

A07 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices

QUESTION & ANSWER FORM

Solicitation Number: 19BE2026Q0005 Project: Rail Waterproofing membrane Questions submission deadline: Sept. 30 2026

Q08 CLIN 0008: How many wall penetrations are to be renewed, and what are their sizes and types?

A08 The contractor is expected to propose a waterproofing system that meets application international building codes and best practices

Q09 Are there any geotechnical or soil contamination reports available for the area?

A09 See A017 as well as the following reference from a larger report pertaining to excavation in the area, but not at this specific site: "The historic fill encountered in the courtyard area contains deleterious material and therefore is not suitable for direct support of new foundations"

Q10 Are there known utilities within the excavation area (e.g., cables, lighting, irrigation)?

A10 There are street lights in the general vicinty which indicates there could be, but it is the contractors responsibility to contact KLIM-CICC to determine locations of official utilities before excavation begins.

Q11 Who owns and operates the rail and metro tunnels, and will the Government coordinate access and approvals with them?

A11 Infrabel operates the rail tunnel. It is expected that the vendor will coordinate access directly with Infrabel.

Q12 Will the Contractor be provided with the contact information for the local municipality and utility permit providers?

A12 The contractor will be provided the contacts from Infrabel who reported the issue to the Embassy. Other contacts are the responsibility of the contractor.

Q13 Are there load, vibration, or equipment restrictions over the tunnel roof? Is vibration or settlement monitoring required?

A13 Construction standards for work near the rail tunnels is publically available via the Infrabel website. Determining this information is the responsibility of the contractor.

https://infrabel.be/nl/construct/contractuele-en-technische-voorschriften

Q14 Is a laydown/site compound area available within the property?

A14 Yes, the site is largely open. Laydown is available.

Q15 Please confirm acceptable working hours given the proximity of residential neighbors.

A15 Working hours must correspond with quiet hours of the commune. This site is located in

Etterbeek.

Q16 Can the scraped asphalt be paved again after restoring the binding properties?

A16 No. Please plan to dispose of scraped asphalt.

Q17 We would like to ask whether we can reuse the existing soil/fill material on site. If the existing material is suitable for reuse, are any tests required to verify its suitability? If testing is required, would the cost and coordination/arrangement of these tests be the Contractor's responsibility?

A17 The existing soil/fill should not be reused for fill on the site as it is known to contain construction debris based on existing reports, though is likely acceptable for landscape fill elsewhere when the contractor is considering recycling vs. disposal. Please see screenshot from a larger geotechnical report for work in the area, but not this specific spot.

Q18 Are the four areas identified in the Attachment 2 site plan (235 / 10K / 10V / 10F / 10W) included within the scope of work?

A18 The main area in questions is 235/10K per the information from Infrabel. The water infiltration is in that area.

Q19 Please confirm whether the following alternative would be acceptable: excavate 1.5 m, cast a new slab, apply the full 790-11 waterproofing system on the positive side, and cover with the required finishes. This option would prevent water from reaching the new slab, as the water source is on the positive side rather than the negative side.

A19 It is up to the contractor to propose their waterproofing system. If this is what is what your company would recommend, then please submit that.

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