How to standardise the unknown information from inspection

The information provided by the desk study and inspection may be incomplete, unclear or missing. In this chapter the standardisation starting points are presented, which help to consider the most realistic case per structural element; foundations, floors, roofs, walls and connections. Use the following guidelines in consultation with the lead engineer.

Foundations

Typology of the building or building part	Foundation width size per wall material and type								Footing columns
	External masonry wall (CS or CMt)		Internal masonry wall (CS or CMt)			Light weight internal “load bearing”			Timber & Masonry	Concrete & Steel
	Single layer	Cavity wall	Single layer	Cavity wall	Single layer over slab on sand	Timber	Steel	Other
1 story per 1950’s	tw* + 400 “masonry stepped” w	–	tw + 400 “masonry stepped”	–	tw + 2ts** (plain concrete)	300	–	–	500x500	–
2 stories per 1950’s	3tw or tw* + 400 “masonry stepped” w	–	3tw or tw* + 400 “masonry stepped”	–	–	–	–	–	800x800	–
1 story post 1950’s (concrete foundation)	tw + 300	500	tw + 300	500	tw + 2ts (plain concrete), tw + 5ts (reinforced concrete) or tw + 10ts (precast concrete)	300	400	400	500x500	700x700
2 stories per 1950’s (concrete foundation)	–	600	tw + 500	600	–	–	–	–	800x800	1000x1000
Notes The units of this table are in mm. This table is for 1 and 2 stories building including attics and for houses located in the Groningen region in case drawings or inspection info is not available. t: CS & CM are Calcium Silicate and Clay Masonry brick walls. w: just for hard clay layer / “vlijlaag” or also for post-1950’s stepped foundation on “stampbeton” and/or soil improvements. tw: in mm is the thickness of the wall either for a since layer wall or the sum of the two layers and the cavity for cavity walls. ts: in mm and is the thickness of the ground level slab floors.

Figure 1 Internal masonry wall over a plain concrete slab.

Figure 2 Internal masonry wall over a reinforced concrete slab.

Figure 3 Masonry stepped foundation.

Figure 4 Cavity wall foundation.

Floors

Unknown		Standardisation
General	Floor material	Check the pictures to get an idea about the used material. Check if the floors above and below are similar. If yes, use the same properties. If no, find similar floors from other objects.
	Presence of finishing layers	Assume there are no finishing layers.
	Ground floor on sand	Do not model the floor.
Timber	Floor board	By looking at the pictures it is usually clear what material is used. If this is not possible, assume the material based on the construction/renovation date; before 1970 planks and after 1970 plates.
	Floor board thickness	Planks: thickness 18 mm and width 165 mm Plates: one layer, 12 mm
	Floor joist direction	Check the pictures to see If the beams or planks are visible and assume accordingly. If this is not possible, assume the shortest distance.
	Floor joist dimensions	Center to center distance: 600 mm Height: 1/20 of the floor joist length Width: 1/3 of the floor joist height
Concrete	Material	There are two main materials that can be used: in-situ and hollow core. By looking the floor from below it is apparent which material is used. If there are joints along the slab, then hollow core is used. If this is not possible, use in-situ. Attention: The joints can be covered so they cannot be seen.
	In-situ concrete thickness	Shortest floor span/25
	Hollow core concrete thickness	Shortest floor span/30 and then decide which characteristic thickness is closer; 150, 200, 260, 320 or 400 mm. Assume thickness of compression layer equal to 50 mm.

Roofs

Unknown		Standardisation
Timber	Presence of timber beams	From the pictures, gather the missing timber beams. However, judge which of them are important for the structure. Avoid modelling every detail.
	Support on cavity walls	Usually, the roof supports on the inner cavity wall.
	Roof board	By looking at the pictures it is usually clear what material is used. If this is not possible, assume the material based on the construction/renovation date; before 1970 planks and after 1970 plates.
	Connection between timber roof and timber attic floor	A beam should be modelled at the intersection of the plane of the roof and the plane of the attic. This beam should have a hinge connection with the adjacent shapes.
	Connection between timber wall plate and masonry wall	Rigid connection
	Connection between timber roof rafters and timber wall plate	Hinge connection
Hardboard and / or Softboard	Presence	Disregard this material as it is not certain if it can provide proper diaphragm action. Consider it as an added mass to the attaching load bearing elements, e.g. rafters, purlins, etc.

Walls

Unknown		Standardisation
Masonry	Material	Assume the material properties based on the renovation stages.
	Thickness	Assume the wall thickness based on the attaching walls.
	Connection	If it is not possible to see from the pictures the wall connection assume that it is connected.
	Cavity wall ties	Basis of Design document (UPR) contains specific guidelines.
	Presence of lintels	Apply lintels to all openings if no information is provided.
	Lintel properties	Material: Linear concrete Width: Width of the attaching wall Height: 100 mm Supporting length: 100 mm

Connections

Unknown	Standardisation
Connection between 1D elements (e.g. beam to beam, beam to column, etc.)	Hinge connection