Old House Joist Splices

[ChaosTheory]

Preface:
I bought an old beat up 1890's 4-square about a year ago and am doing a complete refurbishment. Having gutted the building and replaced the foundation, now I am on to dealing with adjustments and improvements to the structure.

Data:
The current issue to deal with is the (1st level ceiling / 2nd level floor) joists. These joists are original 2x10 (width dimension up to 2.25) and span front to back being 16"OC. The house is 24ft in depth. The joists are supported midspan, and are an average of 18-20ft in length. A second "splice" joist is usually about 8ft in length giving a splice overlap of greater than 2 ft, average of 4 ft. This splice is of course not supported as it would be in normal construction today. The splices are staggered such that adjacent joists are not spliced on at the same end, in the A-B-A-B... pattern.
(It does not let me post the picture so look at my blog if you want one)

Concerns:
(a) While some might say, "cut and replace", I would rather avoid that as I am simply trying to finish the house with as little cost as possible and am now forced to sell off tools and do medical studies for every expense.
(b) This is small town NE with only 1 building inspector who covers all permits. I doubt that there have been anything more than 3-4 rebuild permits in the last 10 year, mostly new construction in the 200k range. I have a reasonable working relationship with The Man but there is no way he is not going to buy off on the "its been that way for 100 years" argument.

Question:
The question therefore is: Is there anyway that I can show to my local inspector that this is a sufficient installation? Surely there is some old official publication that covers the usage of unsupported splices in residential construction?

Any thoughts would be greatly appreciated.
Pictures are on my blog: cedarshed dot blogspot dot com

[Don_P]

Yes, this was not unusual practice, the splice ideally was at the "inflection point" about 1/4 span where bending stress passes through zero on a continuous span over multiple support points. An old engineer should be able to show it works by calculation. A newer variation called the "in-line" joist system appears in my '75 copy of "wood frame house construction" USDA, Forest Service, Ag Handbook #73

Actually at those dimensions, barring other damage, it probably calcs out if you mentally eliminate every other joist.

[ChaosTheory]

Thanks for the reference.
In my spare time I am working on a mechanical engineering degree and have examined every since connection from that perspective.
Is the primary reason to do the splice at the inflection point to keep from loading the joists with a moment load?

[Don_P]

Yes, if you investigate splices in timberframing they were typically not over the post, a point of maximum moment, but over a brace, near the inflection point. I take some issue with the logic, kinda in a hurry at the moment, the snow is tapering off so I'm heading in. Also investigate the condition "beam overhanging support". This is the way I view it. The short joist is looked at as a point load resting on the end of the overhanging beam... more conservative. We can discuss more later if you like.