Sample 1			Sample 2			Sample 3			Sample 4
class of loading /kN	deflection /mm	stiffness reducing factor	class of loading /kN	deflection /mm	stiffness reducing factor	class of loading /kN	deflection /mm	stiffness reducing factor	class of loading /kN	deflection /mm	stiffness reducing factor
20	1.50	1.00	20	2.10	1.00	20	2.10	1.00	20	1.92	1.00
30	2.70	0.83	30	3.48	0.91	30	3.54	0.89	30	3.48	0.83
40	4.56	0.66	40	3.30	1.27	40	4.80	0.88	40	4.50	0.85
50	5.22	0.72	50	5.88	0.89	50	6.12	0.86	50	5.40	0.89
60	6.78	0.66	60	7.80	0.81	60	8.10	0.78	60	6.78	0.85
70	7.80	0.67	65	14.10	0.48	65	14.10	0.48	70	15.60	0.43
80	22.20	0.27	-	-	-	68	20.52	0.35	-	-	-
84	25.92	0.24	-	-	-	-	-	-	-	-	-