When it comes to concrete and steel, there were few standards for materials and design prior to about 1920, and you may not find any prior to 1905, at least that is my experience. Reinforced concrete technology was largely proprietary prior to about 1910 - as such the first multi-story reinforced concrete building in the UK (Weaver's Warehouse 1897 to 1906 I believe) was built under license.
The Civil Engineer's Handbook in the UK can be a good guide for what was going on in the early days (UK and Commonwealth), and the Institution of Civil Engineers library has older copies of this. For example, the water to cement ratio was found in the 1923 version of the Handbook in the UK for the first time (known as the Abrams Ratio and was expressed as volume of cement to volume of water rather than today's w/c m/m ratio).
The design of the Weaver's Warehouse indicated that the use of reinforcement at that time resulted in loads being supported by an 'arching' effect rather than the 'ductility' design approach of present. This means that older structures could be at greater risk of brittle failure modes. I suspect that this is because there was little knowledge of embedment length, etc prior to the 1930's, and steel was often 'fixed' at the ends. The proprietary construction process of that project required that the slabs/beams be load tested as the structure was built.
From memory the first codes for steel and cement (eg BS 12) in the UK were released in the early 1900's, around about 1906 or so, I don't have the exact dates. Cements were far more coarsely ground in those days, and chemically very much different. There was little C3A and gypsum added, for example, prior to about 1920, as it was introduced at a later date when manufacturers found it could reduce the energy and cost of production. Furthermore, because little was known about the bonding of reinforcing steel and embedment length, it was often smooth, not deformed, prior to 1920.
On the other side of the Atlantic, the American Concrete Institute was founded around 1904, and the first building regulations were adopted around 1910 with a number of standards in place around 1912. The Portland Cement Assocation, with Duff Abrams later as its first Chief Engineer, was founded around 1917. Abrams was to originate the ACI concrete mix design method, the concept of water to cement ratio and reinforcing steel bonding capacity in the US.
What I have found in the US and Europe on structures dating back to about 1910 (but mostly during the 1920's) is that you can find just about anything, and testing is strongly advised. It is not unusual to find concrete typically designed and produced on a loose volume basis (ie by scoop or shovel 1:2:4 and no water to cement ratio). One project we looked at, an older bridge foundation and deck, had concrete mixture composition that varied from one end of the bridge to the other: the aggregates were a rounded river gravel on one end and the other end had a crushed granite, and they blended together as they reached the centre.
Another significant issue is the foundation design and construction. You can find anything. I have seen structures carrying load successfully for 50 years or more but with timber piles that were located only half under the cap (ie extending beyond the edges). So again there is no substitute for investigation and/or testing.
For concrete there is an international standard BS EN 13791 that includes statistical strength assessment for structures where no history of the structure is known. This can be of use for comparing the concrete to modern structural codes. But if there is to be a change of loading condition then there is no substitute for identifying cover depths and steel/section geometry using non-destructive tests. And of course reinforcing steel corrosion can be a significant factor.
For structural steel a critical issue is often the bolts/welds as well as the sections. The assessment is very much of an art here, and may require radiographic/ultrasonic/torque testing if the situation demands it. Very old steel structures are often riveted which introduces further complexity. As far as I am aware, there aren't any historical guides on bolts and rivets. Previous posts have given some references that could be of use for the sections. If in doubt about a steel structure, you can obtain coupons from the sections and have them tested for tensile capacity and ductility.