EN 1738-1998 pdf download.Determination of steel stresses in unloaded reinforced components made of autoclaved aerated concrete.
This EN 1738 specifies a method of determmirig the steel stresses in longitudinal bars at nudsl)an of unloa(led reinforce( I components made of autoclaved aerated concrete (AAC) according to iwEN 12602.
2 Normative references
Tins ELlrOIWaIl Stafl(Lard incorporates by (fated or undated reference, provisions from other publications. These normative references are cited at the appropnate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporate(l in it by aIflefl(lnleflt or revision. For undated references the latest edition of the publication referred to apI)hes.
EN 1352, I)efri7n iiuit ion of 51(1! IC modulus of elasticity under compression of autoela red aerated concrete and of 11gb (weigh.! aggregate concrete with open structure.
EN 1313, Determination of mois(urc content qf a ii toeki red aerated concrete.
EN 1356: 1996, Peifi)?7nii nee test for prefabricated rcimfomrcd components of autoeki red aerated concrete oi lightu’eujhl aggm”gate concrete with open structure under tsrinsvcrse load.
EN 10002-2, Metallic materials — Tens lie testing — Pail 2: Verification of the force sneasu ring system of the tensile testing imiachines.
prEN 1 260’2, Prefabricated rr’ufmred components of (1 ut ocla i’ed aerrik’d concirfr.
The test equipment shall be checked when the type of strain gauges or glue is changed. The following procedure shall be applied.
—A pair of strain gauges are glued to asteel bar of the same type as normally Use(1 in the CoIllpotWfltS.
— 11W steel bar is subjected to tension in a testing machine.
— The strain values of the strain gauges are deternuned at the stress levels of (50, 100 and 150) N/nun’2 which shall be maintained with an accuracy of 1 96.
The measured strain values shall not deviate by more than ±5 % from those calculated from the loads indicated by the testing machine and from the cross-sectional area of the bar, assuming a mxlulus of elasticity of the steel of 200000 N/nun.
The results of this test shall be recorded to be made avallal)le if requured.
5 Test specimens
5.1 Sample
The sample for the preparation of the test specimens shall be taken in such a manner that it is representatjve of the product to be investigated, The direction of rise of the mass during manufacture shall be marked on the componenLs.
NOTE For I he siibwqiient evaliiat ion of test results it is of great advantage if reliable data are available on the (‘Onlj)4flIeIltS to be tested and their load history. if relevant.
5.2 Shape and size of test specimens
The test specinwns are full-size reinforced
AAC—comixinei its.
5.3 Conditioning of test specimens
Prior to testing, the (‘OflII)Ofleflt. shall be stored for at least seven days at a temperature of (15 to :30) °C and a relative humidity of (4() to 65) 96. The storage conditions shall be as constant as possible.
1)uring this time the component shall be placed on one of its longitudinal edges on two supports as shown in FIgure 1, so that stresses (tile to its own weight are insignificant. One of the two supports shall be flloVeal)le in the longitu(Iinal (lirect ion of the component (e.g. a loose roller) in order to avoid any longit 11(linal restraint.
6 lèsting procedure
6.1 Measuring of camber
The cainl)er of the uflloa(le(l component shall be measured at midspan, the component remaining in the same posit]( )fl as (hiring the conditiornng. Measurements shall be taken at both the upper and the lower edge. Any suitable method may be used (see e.g. EN 1356:1996, 5.2), iroded that it allows an accuracy of ±1 nuu.
6.2 Determination of steel strains During the whole I)roce(lLIre the component shall remain in the same position and under the same climatic conditions as during the conditioning. Normally, the steel strains are measured on three longitudinal bars at the same face of the component. representing the top, mi(l(lle, and bottoni position.s during casting.
The bars shall be exposed at nudspan over a length of about 200 nuii (see Figure 1), and the necessary quantity of the surrounding AAC shall be taken away in order to allow the application of the strain gauges. The corrosion protective coating shall be also removed and the steel surface carefully cleaned.EN 1738-1998 pdf download.