In situ evaluation of a timber structure using a drilling resistance device. Case study: Kjøpmannsgata 27, Trondheim (Norway)

Figures & data

1 Bryggene along the river Nidelva

2 Kjøpmannsgata 27

3 Methodology

4 Main areas of investigation

5 Analysis of beam cross-section

6 Grid used for the identification of the elements. Basement plan

7 Location of the drilling resistance measurement points

Table 1 Extract from the table of observations of this investigation

	Moisture content	Visible decay	Internal decay
Columns
0J5	34–45%	Superficial decay in the area in contact with the ground	No internal decay is shown by the drilling resistance device
0J4a	36–45%	Superficial decay in the area in contact with the ground	No internal decay is shown by the drilling resistance device
…	…	…	…
Foundation beams
0J4a-0I4	36–38%	Superficial decay at the ends	No internal decay is shown by the drilling resistance device
0H4-0I4	38–45%	Superficial decay along the full length of the beam	Superficial decay. The graph shows low resistance in the proximity of the surface
0H4-0H5	38–45%	Most of the element is missing. Cross-section reduction is higher than 30%. The remains of the beam are completely rotten and decayed by humidity	The graph shows low resistance in the proximity of the surface. Void of 30% of the cross-section located at the centre shows no resistance. Another 23% of the cross-section shows poor resistance to the drilling device

8 Drilling resistance graph for Column 0-B3

9 Drilling resistance graph for foundation beam 0H4-0H5

10 Map showing condition of the foundation beams

Table 2 Classification of foundation beams

Foundation beams	Missing beams	No damage	Superficial decay	Cross-section loss <30%	Cross-section loss >30%
67	27 (40.2%)	13 (19%)	18 (26.8%)	2 (4%)	7 (10%)