Technical report # 4

Technical Report

Volvo Service Center "Concrete Floor Analysis"

Client: SPRING GROUP.

1. Problem Description:

a Reinforced concrete slab with (150 mm) thickness, under a service loading of

Transport (Carriage) Trailer with total weight of (58.5 TON), according to AASHTO

& ACI.318.08 international codes.

Attached documents:

Table (4.8) Arrangement of Trailer axel loads for both wheel side (left & right) and

geometrical dimensions for trailer wheel axle.

Fig 1.1 first case study “Single wheel axel located on Edge of Slab”

Fig. 1.2 second case study “Single wheel axel located on middle-span of Slab”

Fig. 1.3 third case study “Double wheels axel located on middle-span of Slab”

Fig 2.2 typical dowelled contraction (reinforced and unreinforced) slab joint

Fig 2.3 typical dowelled expansion slab joint

2. Basic assumption:

2.1 Concrete compressive strength is 35 MPa and steel yielding strength is 420

Mpa for BRC steel mesh.

2.2 Soil minimum bearing capacity is 14 TON/m2.

2.3 Vertical applied pressure (axle loads) is uniformly distributed form top

surface to bot by angle of (45 degree).

2.4 Soil bearing strength calculation is based on Safety Factor of (F.S. = 3.0).

3. Strength Requirements:

3.1 concrete slab checking part:

3.1.1 bearing strength

3.1.2 bunching (sheering) strength

3.1.3 serviceability “max allowable deflection”

3.2 soil foundation checking part:

3.2.1 contact pressure “soil bearing capacity”

3.2.2 max allowable settlement “international code req. ”

4. stress calculation:

4.1 Soil Part:

Wheel axle loading is based on attached Table (4.8) and Table (FLM4) in Euro-code

number (EN 1991-2) for both: Trailer Truck and Cargo Carriage Truck. Taking the

worst-case scenario (1st and 3

rd item in attached table 4.8) to represent our validation

calculation.

FIRST CASE: refer to attached figure number (1.1)

surface pressure = (applied load, ton) / (contact surface area, m2)

q1 = P / A

q1 = 3.5 / (0.22 * 0.32) = 49.72 ton/m2

top soil pressure = surface pressure * reduction factor

q2 = q1 * A1 / A2

q2 = 49.72 * (0.22 * 0.32) / (0.62*0.37) = 15.26 ton/m2 > 14.0 ton/m

2 (NOT OK.)

Note: the probability of above “problem” result is only occurs at joint area which

represent no more than 5% of total concrete slab area, and this problem could be

resolved by increasing the strength of the expansion joint “as shown in Fig.(2.2) for

reinforced joint”.

SECOND CASE: refer to attached figure number (1.2)

surface pressure = (applied load, ton) / (contact surface area, m2)

q1 = P / A

q1 = 3.5 / (0.22 * 0.32) = 49.72 ton/m2

top soil pressure = surface pressure * reduction factor

q2 = q1 * A1 / A2

q2 = 49.72 * (0.22 * 0.32) / (0.62*0.52) = 10.84 ton/m2 < 14.0 ton/m

2 (OK.)

THIRD CASE: refer to attached figure number (1.3)

surface pressure = (applied load, ton) / (contact surface area, m2)

q1 = P / A

q1 = 6.5 / (0.54 * 0.32) = 37.572 ton/m2

top soil pressure = surface pressure * reduction factor

q2 = q1 * A1 / A2

q2 = 37.572 * (0.54 * 0.32) / (0.84*0.62) = 12.476 ton/m2 < 14.0 ton/m

2 (OK.)

Allowable settlement of foundation was checked by structural analysis software

“Staad.pro” and the resulted settlement is 11.8 mm less that 25 mm, which is accepted.

__________________

4.2 Concrete Slab Part:

Bearing (crushing strength):

a. Allowable bearing stress (on full area) = 0.25 *fć

= 0.25 * 35 = 8.75 MPa

contact pressure (3rd case) = 37.572 * 0.01 = 0.376 << 8.75 (OK.)

b. Allowable bearing stress (on one-third area) = 0.375 *fć

= 0.375 * 35 = 13.13 MPa

contact pressure (1st

case) = 49.72 * 0.01 = 0.497 << 13.3 (OK.)

Punching strength:

a. Nominal slab shear strength is :

√ ̅

√

Applied punching load (1rd case), P = 3.5 < 10.476 ton

b. Nominal slab shear strength is:

√ ̅

√

Applied punching load (3rd case), P = 6.4 < 22.63 ton

320

220

Fig. (1.1) First case - Loading Area Wheel Axle load on Edge of Concrete Slab

P

320

220

Fig. (1.1) Second case - Loading Area Single Wheel Axle load at middle of Concrete Slab

P

320

540

Fig. (1.3) Third Case-Loading Area Double Wheels (Tandem) Axle load at middle of of Concrete Slab

2P