Humboldt H-3033A Concrete Beam Tester - Manual (Page 3)

Introduction
These self-contained portable concrete beam testers accurately and easily
determine flexural strengths of 6 x 6" cross-section test beams. Hydraulically-
driven, these Beam Breakers use a center-point loading method with
continuous readings to the break. The gauge resets to zero (0) for repeat tests.
These lightweight aluminum units have dual registration of modulus of rupture
between 10,000 lbf. and 0–4,500 kgf. Shipping weight of each is 65 lbs. (29kg)
Product Description— H-3030A
The Humboldt Manufacturing Co Model H-3030, Concrete Beam Tester, is
a lightweight portable unit to easily determine the flexural strength of up to
6x6x30" test beams. Hydraulically driven, it uses the center-point loading
method defined in ASTM C293 and AASHO T177 with continuous dial gauge
readings.
Physical Specifications:
Function Modulus of rupture of concrete beams using
center point loading
Range 0 - 1,666 lbf/in 2
0 - 15,000 lbf
Shipping weight: lb
Overall height: "
Base dimension: "
Theory Of Operation
The modulus of rupture
1 is defined as:
(1)
where:
R = modulus of rupture in lbf/in 2
b = average specimen width in inches
P = maximum applied load in lbf d = average specimen depth in inches
L = span length in inches
1 R is actually the stress in lbf/in 2 of the outer fibers of the beam (in compression at the top,
in tension at the bottom).
Where: S = stress at top or bottom of the beam in lbf/in 2
M = bending moment (P/2 x L/2)
c = distance from centroid to top of beam (d/2)
I = Inertia about the centroid (bd 3 /12)